81936572 has 6 divisors (see below), whose sum is σ = 143389008. Its totient is φ = 40968284.

The previous prime is 81936563. The next prime is 81936623. The reversal of 81936572 is 27563918.

It is a super-2 number, since 2×81936572² = 13427203662222368, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10242068 + ... + 10242075.

It is an arithmetic number, because the mean of its divisors is an integer number (23898168).

Almost surely, 2^81936572 is an apocalyptic number.

It is an amenable number.

81936572 is a deficient number, since it is larger than the sum of its proper divisors (61452436).

81936572 is a wasteful number, since it uses less digits than its factorization.

81936572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20484147 (or 20484145 counting only the distinct ones).

The product of its digits is 90720, while the sum is 41.

The square root of 81936572 is about 9051.8822352039. The cubic root of 81936572 is about 434.3361027019.

The spelling of 81936572 in words is "eighty-one million, nine hundred thirty-six thousand, five hundred seventy-two".