79769721991 has 2 divisors, whose sum is σ = 79769721992. Its totient is φ = 79769721990.

The previous prime is 79769721931. The next prime is 79769722003. The reversal of 79769721991 is 19912796797.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 79769721991 - 2³⁵ = 45409983623 is a prime.

It is a super-3 number, since 3×79769721991³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79769721931) 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, 39884860995 + 39884860996.

It is an arithmetic number, because the mean of its divisors is an integer number (39884860996).

Almost surely, 2^79769721991 is an apocalyptic number.

79769721991 is a deficient number, since it is larger than the sum of its proper divisors (1).

79769721991 is an equidigital number, since it uses as much as digits as its factorization.

79769721991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27005076, while the sum is 67.

The spelling of 79769721991 in words is "seventy-nine billion, seven hundred sixty-nine million, seven hundred twenty-one thousand, nine hundred ninety-one".