81553260525 has 96 divisors (see below), whose sum is σ = 148974215040. Its totient is φ = 39037440000.

The previous prime is 81553260521. The next prime is 81553260533. The reversal of 81553260525 is 52506235518.

It is not a de Polignac number, because 81553260525 - 2² = 81553260521 is a prime.

It is a super-3 number, since 3×81553260525³ (a number of 34 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81553260521) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 34078729 + ... + 34081121.

It is an arithmetic number, because the mean of its divisors is an integer number (1551814740).

Almost surely, 2^81553260525 is an apocalyptic number.

It is an amenable number.

81553260525 is a deficient number, since it is larger than the sum of its proper divisors (67420954515).

81553260525 is a wasteful number, since it uses less digits than its factorization.

81553260525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2927 (or 2922 counting only the distinct ones).

The product of its (nonzero) digits is 360000, while the sum is 42.

The spelling of 81553260525 in words is "eighty-one billion, five hundred fifty-three million, two hundred sixty thousand, five hundred twenty-five".