81646764 has 24 divisors (see below), whose sum is σ = 190794240. Its totient is φ = 27174864.

The previous prime is 81646739. The next prime is 81646769. The reversal of 81646764 is 46764618.

It is not an unprimeable number, because it can be changed into a prime (81646769) 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, 3897 + ... + 13359.

It is an arithmetic number, because the mean of its divisors is an integer number (7949760).

Almost surely, 2^81646764 is an apocalyptic number.

It is an amenable number.

81646764 is an abundant number, since it is smaller than the sum of its proper divisors (109147476).

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

81646764 is a wasteful number, since it uses less digits than its factorization.

81646764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10189 (or 10187 counting only the distinct ones).

The product of its digits is 193536, while the sum is 42.

The square root of 81646764 is about 9035.8598926721. The cubic root of 81646764 is about 433.8234184342.

The spelling of 81646764 in words is "eighty-one million, six hundred forty-six thousand, seven hundred sixty-four".