81569356 has 24 divisors (see below), whose sum is σ = 163920960. Its totient is φ = 35125200.

The previous prime is 81569353. The next prime is 81569357. The reversal of 81569356 is 65396518.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81569353) 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, 47950 + ... + 49621.

It is an arithmetic number, because the mean of its divisors is an integer number (6830040).

Almost surely, 2^81569356 is an apocalyptic number.

It is an amenable number.

81569356 is an abundant number, since it is smaller than the sum of its proper divisors (82351604).

81569356 is a wasteful number, since it uses less digits than its factorization.

81569356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97605 (or 97603 counting only the distinct ones).

The product of its digits is 194400, while the sum is 43.

The square root of 81569356 is about 9031.5754993246. The cubic root of 81569356 is about 433.6862747199.

The spelling of 81569356 in words is "eighty-one million, five hundred sixty-nine thousand, three hundred fifty-six".