54

Previous  ... Next

Number

$54$ (fifty-four) is:

$2 \times 3^3$

The $2$nd integer solution to $\map {\sigma_1} n = \map {\sigma_1} {n + 2}$ after $33$:

$\map {\sigma_1} {54} = 120 = \map {\sigma_1} {56}$

The $10$th positive integer $n$ after $5$, $11$, $17$, $23$, $29$, $30$, $36$, $42$, $48$ such that no factorial of an integer can end with $n$ zeroes.

The $12$th semiperfect number after $6$, $12$, $18$, $20$, $24$, $28$, $30$, $36$, $40$, $42$, $48$:

$54 = 9 + 18 + 27$

The $32$nd positive integer after $2$, $3$, $4$, $7$, $8$, $\ldots$, $33$, $37$, $38$, $42$, $43$, $44$, $45$, $46$, $49$, $50$ which cannot be expressed as the sum of distinct pentagonal numbers.

The $35$th (strictly) positive integer after $1$, $2$, $3$, $\ldots$, $37$, $38$, $42$, $43$, $44$, $48$, $49$, $50$ which cannot be expressed as the sum of distinct primes of the form $6 n - 1$

Also see

• Previous  ... Next: Integers Differing by 2 with Same Divisor Sum
• Previous  ... Next: Semiperfect Number
• Previous  ... Next: Numbers of Zeroes that Factorial does not end with
• Previous  ... Next: Numbers not Expressible as Sum of Distinct Pentagonal Numbers
• Previous  ... Next: Integers not Expressible as Sum of Distinct Primes of form 6n-1