81930425 has 6 divisors (see below), whose sum is σ = 101593758. Its totient is φ = 65544320.

The previous prime is 81930403. The next prime is 81930449. The reversal of 81930425 is 52403918.

It can be written as a sum of positive squares in 3 ways, for example, as 23116864 + 58813561 = 4808^2 + 7669^2 .

It is not a de Polignac number, because 81930425 - 2⁸ = 81930169 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81930391 and 81930400.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1638584 + ... + 1638633.

It is an arithmetic number, because the mean of its divisors is an integer number (16932293).

Almost surely, 2^81930425 is an apocalyptic number.

It is an amenable number.

81930425 is a deficient number, since it is larger than the sum of its proper divisors (19663333).

81930425 is a wasteful number, since it uses less digits than its factorization.

81930425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3277227 (or 3277222 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 81930425 is about 9051.5426861944. The cubic root of 81930425 is about 434.3252409230.

The spelling of 81930425 in words is "eighty-one million, nine hundred thirty thousand, four hundred twenty-five".