81625125 has 16 divisors (see below), whose sum is σ = 135824832. Its totient is φ = 43533200.

The previous prime is 81625087. The next prime is 81625127. The reversal of 81625125 is 52152618.

It is not a de Polignac number, because 81625125 - 2¹⁶ = 81559589 is a prime.

It is a super-2 number, since 2×81625125² = 13325322062531250, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81625092 and 81625101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81625127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108459 + ... + 109208.

It is an arithmetic number, because the mean of its divisors is an integer number (8489052).

Almost surely, 2^81625125 is an apocalyptic number.

It is an amenable number.

81625125 is a deficient number, since it is larger than the sum of its proper divisors (54199707).

81625125 is a wasteful number, since it uses less digits than its factorization.

81625125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217685 (or 217675 counting only the distinct ones).

The product of its digits is 4800, while the sum is 30.

The square root of 81625125 is about 9034.6624176003. The cubic root of 81625125 is about 433.7850893609.

The spelling of 81625125 in words is "eighty-one million, six hundred twenty-five thousand, one hundred twenty-five".