81823885 has 24 divisors (see below), whose sum is σ = 116001504. Its totient is φ = 54924480.

The previous prime is 81823871. The next prime is 81823913. The reversal of 81823885 is 58832818.

It is not a de Polignac number, because 81823885 - 2²¹ = 79726733 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 4894 + ... + 13696.

It is an arithmetic number, because the mean of its divisors is an integer number (4833396).

Almost surely, 2^81823885 is an apocalyptic number.

It is an amenable number.

81823885 is a deficient number, since it is larger than the sum of its proper divisors (34177619).

81823885 is a wasteful number, since it uses less digits than its factorization.

81823885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8845 (or 8832 counting only the distinct ones).

The product of its digits is 122880, while the sum is 43.

The square root of 81823885 is about 9045.6555870760. The cubic root of 81823885 is about 434.1368978541.

The spelling of 81823885 in words is "eighty-one million, eight hundred twenty-three thousand, eight hundred eighty-five".