81520900265 has 16 divisors (see below), whose sum is σ = 111812987520. Its totient is φ = 55893598080.

The previous prime is 81520900249. The next prime is 81520900267. The reversal of 81520900265 is 56200902518.

It is not a de Polignac number, because 81520900265 - 2⁴ = 81520900249 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81520900267) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184070 + ... + 443760.

It is an arithmetic number, because the mean of its divisors is an integer number (6988311720).

Almost surely, 2^81520900265 is an apocalyptic number.

It is an amenable number.

81520900265 is a deficient number, since it is larger than the sum of its proper divisors (30292087255).

81520900265 is a wasteful number, since it uses less digits than its factorization.

81520900265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268672.

The product of its (nonzero) digits is 43200, while the sum is 38.

The spelling of 81520900265 in words is "eighty-one billion, five hundred twenty million, nine hundred thousand, two hundred sixty-five".