79813121 has 2 divisors, whose sum is σ = 79813122. Its totient is φ = 79813120.

The previous prime is 79813109. The next prime is 79813157. The reversal of 79813121 is 12131897.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50922496 + 28890625 = 7136^2 + 5375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79813121 is a prime.

It is not a weakly prime, because it can be changed into another prime (79813021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39906560 + 39906561.

It is an arithmetic number, because the mean of its divisors is an integer number (39906561).

Almost surely, 2^79813121 is an apocalyptic number.

It is an amenable number.

79813121 is a deficient number, since it is larger than the sum of its proper divisors (1).

79813121 is an equidigital number, since it uses as much as digits as its factorization.

79813121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 32.

The square root of 79813121 is about 8933.8189482438. The cubic root of 79813121 is about 430.5511609131.

The spelling of 79813121 in words is "seventy-nine million, eight hundred thirteen thousand, one hundred twenty-one".