81303564 has 24 divisors (see below), whose sum is σ = 189968688. Its totient is φ = 27064000.

The previous prime is 81303553. The next prime is 81303569. The reversal of 81303564 is 46530318.

It is a super-2 number, since 2×81303564² = 13220539038204192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81303569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5314 + ... + 13814.

It is an arithmetic number, because the mean of its divisors is an integer number (7915362).

Almost surely, 2^81303564 is an apocalyptic number.

It is an amenable number.

81303564 is an abundant number, since it is smaller than the sum of its proper divisors (108665124).

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

81303564 is a wasteful number, since it uses less digits than its factorization.

81303564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9305 (or 9303 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 81303564 is about 9016.8488952627. The cubic root of 81303564 is about 433.2147096734.

The spelling of 81303564 in words is "eighty-one million, three hundred three thousand, five hundred sixty-four".