81613877 has 2 divisors, whose sum is σ = 81613878. Its totient is φ = 81613876.

The previous prime is 81613849. The next prime is 81613901. The reversal of 81613877 is 77831618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63856081 + 17757796 = 7991^2 + 4214^2 .

It is a cyclic number.

It is not a de Polignac number, because 81613877 - 2⁶ = 81613813 is a prime.

It is a super-2 number, since 2×81613877² = 13321649837942258, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81616877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40806938 + 40806939.

It is an arithmetic number, because the mean of its divisors is an integer number (40806939).

Almost surely, 2^81613877 is an apocalyptic number.

It is an amenable number.

81613877 is a deficient number, since it is larger than the sum of its proper divisors (1).

81613877 is an equidigital number, since it uses as much as digits as its factorization.

81613877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 41.

The square root of 81613877 is about 9034.0399047159. The cubic root of 81613877 is about 433.7651631482.

The spelling of 81613877 in words is "eighty-one million, six hundred thirteen thousand, eight hundred seventy-seven".