81388125 has 160 divisors (see below), whose sum is σ = 188939520. Its totient is φ = 33696000.

The previous prime is 81388103. The next prime is 81388147. The reversal of 81388125 is 52188318.

It is an interprime number because it is at equal distance from previous prime (81388103) and next prime (81388147).

It is not a de Polignac number, because 81388125 - 2⁵ = 81388093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81388125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 1535599 + ... + 1535651.

It is an arithmetic number, because the mean of its divisors is an integer number (1180872).

Almost surely, 2^81388125 is an apocalyptic number.

It is an amenable number.

81388125 is an abundant number, since it is smaller than the sum of its proper divisors (107551395).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81388125 is a wasteful number, since it uses less digits than its factorization.

81388125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102 (or 81 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 81388125 is about 9021.5367316217. The cubic root of 81388125 is about 433.3648481353.

The spelling of 81388125 in words is "eighty-one million, three hundred eighty-eight thousand, one hundred twenty-five".