81255825 has 96 divisors (see below), whose sum is σ = 176774400. Its totient is φ = 35804160.

The previous prime is 81255817. The next prime is 81255829. The reversal of 81255825 is 52855218.

81255825 is a `hidden beast` number, since 81 + 2 + 558 + 25 = 666.

It is not a de Polignac number, because 81255825 - 2³ = 81255817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81255825.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81255829) 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, 136729 + ... + 137321.

It is an arithmetic number, because the mean of its divisors is an integer number (1841400).

Almost surely, 2^81255825 is an apocalyptic number.

It is an amenable number.

81255825 is an abundant number, since it is smaller than the sum of its proper divisors (95518575).

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

81255825 is a wasteful number, since it uses less digits than its factorization.

81255825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648 (or 637 counting only the distinct ones).

The product of its digits is 32000, while the sum is 36.

The square root of 81255825 is about 9014.2012957333. The cubic root of 81255825 is about 433.1299028699.

The spelling of 81255825 in words is "eighty-one million, two hundred fifty-five thousand, eight hundred twenty-five".