81930825 has 24 divisors (see below), whose sum is σ = 150511200. Its totient is φ = 43696080.

The previous prime is 81930817. The next prime is 81930847. The reversal of 81930825 is 52803918.

It is not a de Polignac number, because 81930825 - 2³ = 81930817 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81930825.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60015 + ... + 61364.

It is an arithmetic number, because the mean of its divisors is an integer number (6271300).

Almost surely, 2^81930825 is an apocalyptic number.

It is an amenable number.

81930825 is a deficient number, since it is larger than the sum of its proper divisors (68580375).

81930825 is a wasteful number, since it uses less digits than its factorization.

81930825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121398 (or 121387 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 81930825 is about 9051.5647818485. The cubic root of 81930825 is about 434.3259477415.

The spelling of 81930825 in words is "eighty-one million, nine hundred thirty thousand, eight hundred twenty-five".