79979989 has 2 divisors, whose sum is σ = 79979990. Its totient is φ = 79979988.

The previous prime is 79979953. The next prime is 79980013. The reversal of 79979989 is 98997997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67519089 + 12460900 = 8217^2 + 3530^2 .

It is a cyclic number.

It is not a de Polignac number, because 79979989 - 2²¹ = 77882837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79979909) 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, 39989994 + 39989995.

It is an arithmetic number, because the mean of its divisors is an integer number (39989995).

Almost surely, 2^79979989 is an apocalyptic number.

It is an amenable number.

79979989 is a deficient number, since it is larger than the sum of its proper divisors (1).

79979989 is an equidigital number, since it uses as much as digits as its factorization.

79979989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23147208, while the sum is 67.

The square root of 79979989 is about 8943.1531911290. The cubic root of 79979989 is about 430.8510080166.

The spelling of 79979989 in words is "seventy-nine million, nine hundred seventy-nine thousand, nine hundred eighty-nine".