81988885 has 16 divisors (see below), whose sum is σ = 107586432. Its totient is φ = 59486400.

The previous prime is 81988853. The next prime is 81988897. The reversal of 81988885 is 58888918.

It is not a de Polignac number, because 81988885 - 2⁵ = 81988853 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25255 + ... + 28315.

It is an arithmetic number, because the mean of its divisors is an integer number (6724152).

Almost surely, 2^81988885 is an apocalyptic number.

It is an amenable number.

81988885 is a deficient number, since it is larger than the sum of its proper divisors (25597547).

81988885 is a wasteful number, since it uses less digits than its factorization.

81988885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3564.

The product of its digits is 1474560, while the sum is 55.

The square root of 81988885 is about 9054.7713941325. The cubic root of 81988885 is about 434.4285180510.

The spelling of 81988885 in words is "eighty-one million, nine hundred eighty-eight thousand, eight hundred eighty-five".