81375125 has 16 divisors (see below), whose sum is σ = 109370352. Its totient is φ = 60091200.

The previous prime is 81375097. The next prime is 81375167. The reversal of 81375125 is 52157318.

It can be written as a sum of positive squares in 8 ways, for example, as 27102436 + 54272689 = 5206^2 + 7367^2 .

It is not a de Polignac number, because 81375125 - 2⁶ = 81375061 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81375091 and 81375100.

It is a congruent number.

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, 23414 + ... + 26663.

It is an arithmetic number, because the mean of its divisors is an integer number (6835647).

Almost surely, 2^81375125 is an apocalyptic number.

It is an amenable number.

81375125 is a deficient number, since it is larger than the sum of its proper divisors (27995227).

81375125 is a wasteful number, since it uses less digits than its factorization.

81375125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50105 (or 50095 counting only the distinct ones).

The product of its digits is 8400, while the sum is 32.

The square root of 81375125 is about 9020.8162047566. The cubic root of 81375125 is about 433.3417733399.

The spelling of 81375125 in words is "eighty-one million, three hundred seventy-five thousand, one hundred twenty-five".