81520504 has 32 divisors (see below), whose sum is σ = 165024720. Its totient is φ = 37529856.

The previous prime is 81520501. The next prime is 81520553. The reversal of 81520504 is 40502518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81520501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56172 + ... + 57604.

Almost surely, 2^81520504 is an apocalyptic number.

It is an amenable number.

81520504 is an abundant number, since it is smaller than the sum of its proper divisors (83504216).

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

81520504 is a wasteful number, since it uses less digits than its factorization.

81520504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999 (or 1995 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 81520504 is about 9028.8705827473. The cubic root of 81520504 is about 433.5996789938.

The spelling of 81520504 in words is "eighty-one million, five hundred twenty thousand, five hundred four".