81375885 has 48 divisors (see below), whose sum is σ = 147363840. Its totient is φ = 41489280.

The previous prime is 81375883. The next prime is 81375887. The reversal of 81375885 is 58857318.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81375883) and next prime (81375887).

It is not a de Polignac number, because 81375885 - 2¹ = 81375883 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81375885.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81375883) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 165490 + ... + 165980.

It is an arithmetic number, because the mean of its divisors is an integer number (3070080).

Almost surely, 2^81375885 is an apocalyptic number.

It is an amenable number.

81375885 is a deficient number, since it is larger than the sum of its proper divisors (65987955).

81375885 is a wasteful number, since it uses less digits than its factorization.

81375885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658 (or 655 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 81375885 is about 9020.8583294496. The cubic root of 81375885 is about 433.3431223956.

The spelling of 81375885 in words is "eighty-one million, three hundred seventy-five thousand, eight hundred eighty-five".