81515264 has 18 divisors (see below), whose sum is σ = 162712620. Its totient is φ = 40757504.

The previous prime is 81515261. The next prime is 81515267. The reversal of 81515264 is 46251518.

It is an interprime number because it is at equal distance from previous prime (81515261) and next prime (81515267).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 81515264.

It is not an unprimeable number, because it can be changed into a prime (81515261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 158954 + ... + 159465.

It is an arithmetic number, because the mean of its divisors is an integer number (9039590).

Almost surely, 2^81515264 is an apocalyptic number.

It is an amenable number.

81515264 is a deficient number, since it is larger than the sum of its proper divisors (81197356).

81515264 is an equidigital number, since it uses as much as digits as its factorization.

81515264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318435 (or 318421 counting only the distinct ones).

The product of its digits is 9600, while the sum is 32.

The square root of 81515264 is about 9028.5803978256. The cubic root of 81515264 is about 433.5903884436.

The spelling of 81515264 in words is "eighty-one million, five hundred fifteen thousand, two hundred sixty-four".