81475725 has 12 divisors (see below), whose sum is σ = 134706656. Its totient is φ = 43453680.

The previous prime is 81475721. The next prime is 81475759. The reversal of 81475725 is 52757418.

It is not a de Polignac number, because 81475725 - 2² = 81475721 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 (81475721) 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, 543097 + ... + 543246.

Almost surely, 2^81475725 is an apocalyptic number.

It is an amenable number.

81475725 is a deficient number, since it is larger than the sum of its proper divisors (53230931).

81475725 is a wasteful number, since it uses less digits than its factorization.

81475725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086356 (or 1086351 counting only the distinct ones).

The product of its digits is 78400, while the sum is 39.

The square root of 81475725 is about 9026.3904746028. The cubic root of 81475725 is about 433.5202727289.

The spelling of 81475725 in words is "eighty-one million, four hundred seventy-five thousand, seven hundred twenty-five".