81599401867 has 2 divisors, whose sum is σ = 81599401868. Its totient is φ = 81599401866.

The previous prime is 81599401861. The next prime is 81599401883. The reversal of 81599401867 is 76810499518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81599401867 - 2¹⁵ = 81599369099 is a prime.

It is not a weakly prime, because it can be changed into another prime (81599401861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40799700933 + 40799700934.

It is an arithmetic number, because the mean of its divisors is an integer number (40799700934).

Almost surely, 2^81599401867 is an apocalyptic number.

81599401867 is a deficient number, since it is larger than the sum of its proper divisors (1).

81599401867 is an equidigital number, since it uses as much as digits as its factorization.

81599401867 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4354560, while the sum is 58.

The spelling of 81599401867 in words is "eighty-one billion, five hundred ninety-nine million, four hundred one thousand, eight hundred sixty-seven".