679877977021 has 2 divisors, whose sum is σ = 679877977022. Its totient is φ = 679877977020.

The previous prime is 679877976917. The next prime is 679877977049. The reversal of 679877977021 is 120779778976.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 678440505625 + 1437471396 = 823675^2 + 37914^2 .

It is a cyclic number.

It is not a de Polignac number, because 679877977021 - 2¹⁷ = 679877845949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (679877977321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339938988510 + 339938988511.

It is an arithmetic number, because the mean of its divisors is an integer number (339938988511).

Almost surely, 2^679877977021 is an apocalyptic number.

It is an amenable number.

679877977021 is a deficient number, since it is larger than the sum of its proper divisors (1).

679877977021 is an equidigital number, since it uses as much as digits as its factorization.

679877977021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 130691232, while the sum is 70.

The spelling of 679877977021 in words is "six hundred seventy-nine billion, eight hundred seventy-seven million, nine hundred seventy-seven thousand, twenty-one".