79456721 has 2 divisors, whose sum is σ = 79456722. Its totient is φ = 79456720.

The previous prime is 79456717. The next prime is 79456757. The reversal of 79456721 is 12765497.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67650625 + 11806096 = 8225^2 + 3436^2 .

It is a cyclic number.

It is not a de Polignac number, because 79456721 - 2² = 79456717 is a prime.

It is equal to p_4639577 and since 79456721 and 4639577 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (79456711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39728360 + 39728361.

It is an arithmetic number, because the mean of its divisors is an integer number (39728361).

Almost surely, 2^79456721 is an apocalyptic number.

It is an amenable number.

79456721 is a deficient number, since it is larger than the sum of its proper divisors (1).

79456721 is an equidigital number, since it uses as much as digits as its factorization.

79456721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105840, while the sum is 41.

The square root of 79456721 is about 8913.8499538639. The cubic root of 79456721 is about 429.9093390981.

The spelling of 79456721 in words is "seventy-nine million, four hundred fifty-six thousand, seven hundred twenty-one".