81512704 has 72 divisors (see below), whose sum is σ = 200312000. Its totient is φ = 32237568.

The previous prime is 81512699. The next prime is 81512719. The reversal of 81512704 is 40721518.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21547 + ... + 25045.

Almost surely, 2^81512704 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 81512704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100156000).

81512704 is an abundant number, since it is smaller than the sum of its proper divisors (118799296).

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

81512704 is a wasteful number, since it uses less digits than its factorization.

81512704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3535 (or 3521 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 81512704 is about 9028.4386247014. The cubic root of 81512704 is about 433.5858494041.

The spelling of 81512704 in words is "eighty-one million, five hundred twelve thousand, seven hundred four".