81936583 has 4 divisors (see below), whose sum is σ = 86756400. Its totient is φ = 77116768.

The previous prime is 81936563. The next prime is 81936623. The reversal of 81936583 is 38563918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 38563918 = 2 ⋅19281959.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81936583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81936523) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 2409883 + ... + 2409916.

It is an arithmetic number, because the mean of its divisors is an integer number (21689100).

Almost surely, 2^81936583 is an apocalyptic number.

81936583 is a deficient number, since it is larger than the sum of its proper divisors (4819817).

81936583 is a wasteful number, since it uses less digits than its factorization.

81936583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4819816.

The product of its digits is 155520, while the sum is 43.

The square root of 81936583 is about 9051.8828428123. The cubic root of 81936583 is about 434.3361221385.

The spelling of 81936583 in words is "eighty-one million, nine hundred thirty-six thousand, five hundred eighty-three".