79312921 has 2 divisors, whose sum is σ = 79312922. Its totient is φ = 79312920.

The previous prime is 79312913. The next prime is 79312943. The reversal of 79312921 is 12921397.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77528025 + 1784896 = 8805^2 + 1336^2 .

It is an emirp because it is prime and its reverse (12921397) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79312921 - 2³ = 79312913 is a prime.

It is not a weakly prime, because it can be changed into another prime (79312621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39656460 + 39656461.

It is an arithmetic number, because the mean of its divisors is an integer number (39656461).

Almost surely, 2^79312921 is an apocalyptic number.

It is an amenable number.

79312921 is a deficient number, since it is larger than the sum of its proper divisors (1).

79312921 is an equidigital number, since it uses as much as digits as its factorization.

79312921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6804, while the sum is 34.

The square root of 79312921 is about 8905.7802016443. The cubic root of 79312921 is about 429.6498339065.

The spelling of 79312921 in words is "seventy-nine million, three hundred twelve thousand, nine hundred twenty-one".