79977817 has 2 divisors, whose sum is σ = 79977818. Its totient is φ = 79977816.

The previous prime is 79977773. The next prime is 79977823. The reversal of 79977817 is 71877997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40589641 + 39388176 = 6371^2 + 6276^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79977817 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (79977827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39988908 + 39988909.

It is an arithmetic number, because the mean of its divisors is an integer number (39988909).

Almost surely, 2^79977817 is an apocalyptic number.

It is an amenable number.

79977817 is a deficient number, since it is larger than the sum of its proper divisors (1).

79977817 is an equidigital number, since it uses as much as digits as its factorization.

79977817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1555848, while the sum is 55.

The square root of 79977817 is about 8943.0317566248. The cubic root of 79977817 is about 430.8471078041.

The spelling of 79977817 in words is "seventy-nine million, nine hundred seventy-seven thousand, eight hundred seventeen".