79979621 has 2 divisors, whose sum is σ = 79979622. Its totient is φ = 79979620.

The previous prime is 79979609. The next prime is 79979623. The reversal of 79979621 is 12697997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69122596 + 10857025 = 8314^2 + 3295^2 .

It is a cyclic number.

It is not a de Polignac number, because 79979621 - 2¹⁰ = 79978597 is a prime.

Together with 79979623, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 79979621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79979623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39989810 + 39989811.

It is an arithmetic number, because the mean of its divisors is an integer number (39989811).

Almost surely, 2^79979621 is an apocalyptic number.

It is an amenable number.

79979621 is a deficient number, since it is larger than the sum of its proper divisors (1).

79979621 is an equidigital number, since it uses as much as digits as its factorization.

79979621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 428652, while the sum is 50.

The square root of 79979621 is about 8943.1326167065. The cubic root of 79979621 is about 430.8503472121.

The spelling of 79979621 in words is "seventy-nine million, nine hundred seventy-nine thousand, six hundred twenty-one".