81393623 has 2 divisors, whose sum is σ = 81393624. Its totient is φ = 81393622.

The previous prime is 81393607. The next prime is 81393643. The reversal of 81393623 is 32639318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81393623 - 2⁴ = 81393607 is a prime.

It is a super-2 number, since 2×81393623² = 13249843730132258, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81393643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40696811 + 40696812.

It is an arithmetic number, because the mean of its divisors is an integer number (40696812).

Almost surely, 2^81393623 is an apocalyptic number.

81393623 is a deficient number, since it is larger than the sum of its proper divisors (1).

81393623 is an equidigital number, since it uses as much as digits as its factorization.

81393623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 35.

The square root of 81393623 is about 9021.8414417457. The cubic root of 81393623 is about 433.3746062595.

The spelling of 81393623 in words is "eighty-one million, three hundred ninety-three thousand, six hundred twenty-three".