81599400277 has 2 divisors, whose sum is σ = 81599400278. Its totient is φ = 81599400276.

The previous prime is 81599400269. The next prime is 81599400283. The reversal of 81599400277 is 77200499518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72274407921 + 9324992356 = 268839^2 + 96566^2 .

It is a cyclic number.

It is not a de Polignac number, because 81599400277 - 2³ = 81599400269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81599400287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40799700138 + 40799700139.

It is an arithmetic number, because the mean of its divisors is an integer number (40799700139).

Almost surely, 2^81599400277 is an apocalyptic number.

It is an amenable number.

81599400277 is a deficient number, since it is larger than the sum of its proper divisors (1).

81599400277 is an equidigital number, since it uses as much as digits as its factorization.

81599400277 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1270080, while the sum is 52.

The spelling of 81599400277 in words is "eighty-one billion, five hundred ninety-nine million, four hundred thousand, two hundred seventy-seven".