81936623 has 2 divisors, whose sum is σ = 81936624. Its totient is φ = 81936622.

The previous prime is 81936563. The next prime is 81936637. The reversal of 81936623 is 32663918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81936623 - 2⁸ = 81936367 is a prime.

It is a super-2 number, since 2×81936623² = 13427220377288258, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81936643) 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 as a sum of consecutive naturals, namely, 40968311 + 40968312.

It is an arithmetic number, because the mean of its divisors is an integer number (40968312).

Almost surely, 2^81936623 is an apocalyptic number.

81936623 is a deficient number, since it is larger than the sum of its proper divisors (1).

81936623 is an equidigital number, since it uses as much as digits as its factorization.

81936623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 38.

The square root of 81936623 is about 9051.8850522971. The cubic root of 81936623 is about 434.3361928169.

The spelling of 81936623 in words is "eighty-one million, nine hundred thirty-six thousand, six hundred twenty-three".