81569625 has 16 divisors (see below), whose sum is σ = 135732480. Its totient is φ = 43503600.

The previous prime is 81569617. The next prime is 81569651. The reversal of 81569625 is 52696518.

It is not a de Polignac number, because 81569625 - 2³ = 81569617 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108385 + ... + 109134.

It is an arithmetic number, because the mean of its divisors is an integer number (8483280).

Almost surely, 2^81569625 is an apocalyptic number.

It is an amenable number.

81569625 is a deficient number, since it is larger than the sum of its proper divisors (54162855).

81569625 is a wasteful number, since it uses less digits than its factorization.

81569625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217537 (or 217527 counting only the distinct ones).

The product of its digits is 129600, while the sum is 42.

The square root of 81569625 is about 9031.5903915091. The cubic root of 81569625 is about 433.6867514572.

The spelling of 81569625 in words is "eighty-one million, five hundred sixty-nine thousand, six hundred twenty-five".