81690008377 has 2 divisors, whose sum is σ = 81690008378. Its totient is φ = 81690008376.

The previous prime is 81690008371. The next prime is 81690008401. The reversal of 81690008377 is 77380009618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53159758096 + 28530250281 = 230564^2 + 168909^2 .

It is a cyclic number.

It is not a de Polignac number, because 81690008377 - 2³ = 81690008369 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81690008377.

It is not a weakly prime, because it can be changed into another prime (81690008371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40845004188 + 40845004189.

It is an arithmetic number, because the mean of its divisors is an integer number (40845004189).

Almost surely, 2^81690008377 is an apocalyptic number.

It is an amenable number.

81690008377 is a deficient number, since it is larger than the sum of its proper divisors (1).

81690008377 is an equidigital number, since it uses as much as digits as its factorization.

81690008377 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 508032, while the sum is 49.

The spelling of 81690008377 in words is "eighty-one billion, six hundred ninety million, eight thousand, three hundred seventy-seven".