79797989 has 2 divisors, whose sum is σ = 79797990. Its totient is φ = 79797988.

The previous prime is 79797961. The next prime is 79797997. The reversal of 79797989 is 98979797.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77141089 + 2656900 = 8783^2 + 1630^2 .

It is a cyclic number.

It is not a de Polignac number, because 79797989 - 2¹² = 79793893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79797889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39898994 + 39898995.

It is an arithmetic number, because the mean of its divisors is an integer number (39898995).

Almost surely, 2^79797989 is an apocalyptic number.

It is an amenable number.

79797989 is a deficient number, since it is larger than the sum of its proper divisors (1).

79797989 is an equidigital number, since it uses as much as digits as its factorization.

79797989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18003384, while the sum is 65.

The square root of 79797989 is about 8932.9720138373. The cubic root of 79797989 is about 430.5239493808.

The spelling of 79797989 in words is "seventy-nine million, seven hundred ninety-seven thousand, nine hundred eighty-nine".