81502575 has 72 divisors (see below), whose sum is σ = 169405824. Its totient is φ = 33844800.

The previous prime is 81502543. The next prime is 81502579. The reversal of 81502575 is 57520518.

It is a happy number.

It is not a de Polignac number, because 81502575 - 2⁵ = 81502543 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81502579) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 62884 + ... + 64166.

Almost surely, 2^81502575 is an apocalyptic number.

81502575 is an abundant number, since it is smaller than the sum of its proper divisors (87903249).

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

81502575 is a wasteful number, since it uses less digits than its factorization.

81502575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325 (or 1309 counting only the distinct ones).

The product of its (nonzero) digits is 14000, while the sum is 33.

The square root of 81502575 is about 9027.8776575671. The cubic root of 81502575 is about 433.5678891239.

The spelling of 81502575 in words is "eighty-one million, five hundred two thousand, five hundred seventy-five".