81574164 has 36 divisors (see below), whose sum is σ = 235659424. Its totient is φ = 23306832.

The previous prime is 81574153. The next prime is 81574219. The reversal of 81574164 is 46147518.

It is a happy number.

81574164 is a `hidden beast` number, since 81 + 574 + 1 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161602 + ... + 162105.

Almost surely, 2^81574164 is an apocalyptic number.

81574164 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

81574164 is an abundant number, since it is smaller than the sum of its proper divisors (154085260).

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

81574164 is a wasteful number, since it uses less digits than its factorization.

81574164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323724 (or 323719 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 81574164 is about 9031.8416726601. The cubic root of 81574164 is about 433.6947955776.

It can be divided in two parts, 8157 and 4164, that added together give a palindrome (12321).

The spelling of 81574164 in words is "eighty-one million, five hundred seventy-four thousand, one hundred sixty-four".