81715925 has 12 divisors (see below), whose sum is σ = 101439936. Its totient is φ = 65300400.

The previous prime is 81715919. The next prime is 81715927. The reversal of 81715925 is 52951718.

It is not a de Polignac number, because 81715925 - 2⁶ = 81715861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81715927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42740 + ... + 44610.

It is an arithmetic number, because the mean of its divisors is an integer number (8453328).

Almost surely, 2^81715925 is an apocalyptic number.

It is an amenable number.

81715925 is a deficient number, since it is larger than the sum of its proper divisors (19724011).

81715925 is a wasteful number, since it uses less digits than its factorization.

81715925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3628 (or 3623 counting only the distinct ones).

The product of its digits is 25200, while the sum is 38.

The square root of 81715925 is about 9039.6861118072. The cubic root of 81715925 is about 433.9458776400.

The spelling of 81715925 in words is "eighty-one million, seven hundred fifteen thousand, nine hundred twenty-five".