79516561 has 2 divisors, whose sum is σ = 79516562. Its totient is φ = 79516560.

The previous prime is 79516559. The next prime is 79516627. The reversal of 79516561 is 16561597.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76475025 + 3041536 = 8745^2 + 1744^2 .

It is a cyclic number.

It is not a de Polignac number, because 79516561 - 2¹ = 79516559 is a prime.

Together with 79516559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (79216561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39758280 + 39758281.

It is an arithmetic number, because the mean of its divisors is an integer number (39758281).

Almost surely, 2^79516561 is an apocalyptic number.

It is an amenable number.

79516561 is a deficient number, since it is larger than the sum of its proper divisors (1).

79516561 is an equidigital number, since it uses as much as digits as its factorization.

79516561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56700, while the sum is 40.

The square root of 79516561 is about 8917.2058964678. The cubic root of 79516561 is about 430.0172356531.

The spelling of 79516561 in words is "seventy-nine million, five hundred sixteen thousand, five hundred sixty-one".