81583164 has 72 divisors (see below), whose sum is σ = 226873920. Its totient is φ = 24561792.

The previous prime is 81583157. The next prime is 81583171. The reversal of 81583164 is 46138518.

It is an interprime number because it is at equal distance from previous prime (81583157) and next prime (81583171).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 20142 + ... + 23850.

Almost surely, 2^81583164 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81583164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113436960).

81583164 is an abundant number, since it is smaller than the sum of its proper divisors (145290756).

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

81583164 is a wasteful number, since it uses less digits than its factorization.

81583164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3779 (or 3774 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81583164 is about 9032.3398961731. The cubic root of 81583164 is about 433.7107447027.

The spelling of 81583164 in words is "eighty-one million, five hundred eighty-three thousand, one hundred sixty-four".