81512736 has 192 divisors, whose sum is σ = 246758400. Its totient is φ = 23417856.

The previous prime is 81512731. The next prime is 81512737. The reversal of 81512736 is 63721518.

It is a super-2 number, since 2×81512736² = 13288652260411392, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81512697 and 81512706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81512731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1216575 + ... + 1216641.

It is an arithmetic number, because the mean of its divisors is an integer number (1285200).

Almost surely, 2^81512736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81512736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123379200).

81512736 is an abundant number, since it is smaller than the sum of its proper divisors (165245664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81512736 is a wasteful number, since it uses less digits than its factorization.

81512736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 143 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 81512736 is about 9028.4403968792. The cubic root of 81512736 is about 433.5859061427.

The spelling of 81512736 in words is "eighty-one million, five hundred twelve thousand, seven hundred thirty-six".