79816621 has 2 divisors, whose sum is σ = 79816622. Its totient is φ = 79816620.

The previous prime is 79816619. The next prime is 79816673. The reversal of 79816621 is 12661897.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78960996 + 855625 = 8886^2 + 925^2 .

It is a cyclic number.

It is not a de Polignac number, because 79816621 - 2¹ = 79816619 is a prime.

Together with 79816619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79816691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39908310 + 39908311.

It is an arithmetic number, because the mean of its divisors is an integer number (39908311).

Almost surely, 2^79816621 is an apocalyptic number.

It is an amenable number.

79816621 is a deficient number, since it is larger than the sum of its proper divisors (1).

79816621 is an equidigital number, since it uses as much as digits as its factorization.

79816621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 40.

The square root of 79816621 is about 8934.0148309705. The cubic root of 79816621 is about 430.5574543939.

The spelling of 79816621 in words is "seventy-nine million, eight hundred sixteen thousand, six hundred twenty-one".