81607643137 has 2 divisors, whose sum is σ = 81607643138. Its totient is φ = 81607643136.

The previous prime is 81607643119. The next prime is 81607643197. The reversal of 81607643137 is 73134670618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48556766736 + 33050876401 = 220356^2 + 181799^2 .

It is a cyclic number.

It is not a de Polignac number, because 81607643137 - 2¹⁵ = 81607610369 is a prime.

It is not a weakly prime, because it can be changed into another prime (81607643197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40803821568 + 40803821569.

It is an arithmetic number, because the mean of its divisors is an integer number (40803821569).

Almost surely, 2^81607643137 is an apocalyptic number.

It is an amenable number.

81607643137 is a deficient number, since it is larger than the sum of its proper divisors (1).

81607643137 is an equidigital number, since it uses as much as digits as its factorization.

81607643137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 508032, while the sum is 46.

The spelling of 81607643137 in words is "eighty-one billion, six hundred seven million, six hundred forty-three thousand, one hundred thirty-seven".