81889125 has 16 divisors (see below), whose sum is σ = 136264128. Its totient is φ = 43674000.

The previous prime is 81889123. The next prime is 81889139. The reversal of 81889125 is 52198818.

It is not a de Polignac number, because 81889125 - 2¹ = 81889123 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81889121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108811 + ... + 109560.

It is an arithmetic number, because the mean of its divisors is an integer number (8516508).

Almost surely, 2^81889125 is an apocalyptic number.

It is an amenable number.

81889125 is a deficient number, since it is larger than the sum of its proper divisors (54375003).

81889125 is a wasteful number, since it uses less digits than its factorization.

81889125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218389 (or 218379 counting only the distinct ones).

The product of its digits is 46080, while the sum is 42.

The square root of 81889125 is about 9049.2610195529. The cubic root of 81889125 is about 434.2522495309.

The spelling of 81889125 in words is "eighty-one million, eight hundred eighty-nine thousand, one hundred twenty-five".