81564474 has 8 divisors (see below), whose sum is σ = 163128960. Its totient is φ = 27188156.

The previous prime is 81564467. The next prime is 81564517. The reversal of 81564474 is 47446518.

It is a sphenic number, since it is the product of 3 distinct primes.

81564474 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6797034 + ... + 6797045.

It is an arithmetic number, because the mean of its divisors is an integer number (20391120).

Almost surely, 2^81564474 is an apocalyptic number.

81564474 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81564474 is a wasteful number, since it uses less digits than its factorization.

81564474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13594084.

The product of its digits is 107520, while the sum is 39.

The square root of 81564474 is about 9031.3052212845. The cubic root of 81564474 is about 433.6776223749.

The spelling of 81564474 in words is "eighty-one million, five hundred sixty-four thousand, four hundred seventy-four".