78857737691 has 2 divisors, whose sum is σ = 78857737692. Its totient is φ = 78857737690.

The previous prime is 78857737681. The next prime is 78857737709. The reversal of 78857737691 is 19673775887.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78857737691 - 2²⁶ = 78790628827 is a prime.

It is a super-2 number, since 2×78857737691² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78857737681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39428868845 + 39428868846.

It is an arithmetic number, because the mean of its divisors is an integer number (39428868846).

Almost surely, 2^78857737691 is an apocalyptic number.

78857737691 is a deficient number, since it is larger than the sum of its proper divisors (1).

78857737691 is an equidigital number, since it uses as much as digits as its factorization.

78857737691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124467840, while the sum is 68.

The spelling of 78857737691 in words is "seventy-eight billion, eight hundred fifty-seven million, seven hundred thirty-seven thousand, six hundred ninety-one".