81569976 has 32 divisors (see below), whose sum is σ = 204716160. Its totient is φ = 27084512.

The previous prime is 81569947. The next prime is 81569977. The reversal of 81569976 is 67996518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81569977) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 150 + ... + 12773.

It is an arithmetic number, because the mean of its divisors is an integer number (6397380).

Almost surely, 2^81569976 is an apocalyptic number.

It is an amenable number.

81569976 is an abundant number, since it is smaller than the sum of its proper divisors (123146184).

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

81569976 is a wasteful number, since it uses less digits than its factorization.

81569976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13195 (or 13191 counting only the distinct ones).

The product of its digits is 816480, while the sum is 51.

The square root of 81569976 is about 9031.6098232818. The cubic root of 81569976 is about 433.6873735182.

The spelling of 81569976 in words is "eighty-one million, five hundred sixty-nine thousand, nine hundred seventy-six".