81188725 has 12 divisors (see below), whose sum is σ = 101132416. Its totient is φ = 64655280.

The previous prime is 81188717. The next prime is 81188741. The reversal of 81188725 is 52788118.

It is not a de Polignac number, because 81188725 - 2³ = 81188717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1707 + ... + 12856.

Almost surely, 2^81188725 is an apocalyptic number.

It is an amenable number.

81188725 is a deficient number, since it is larger than the sum of its proper divisors (19943691).

81188725 is a wasteful number, since it uses less digits than its factorization.

81188725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14796 (or 14791 counting only the distinct ones).

The product of its digits is 35840, while the sum is 40.

The square root of 81188725 is about 9010.4786221377. The cubic root of 81188725 is about 433.0106456962.

The spelling of 81188725 in words is "eighty-one million, one hundred eighty-eight thousand, seven hundred twenty-five".