79668581 has 2 divisors, whose sum is σ = 79668582. Its totient is φ = 79668580.

The previous prime is 79668571. The next prime is 79668599. The reversal of 79668581 is 18586697.

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., 58277956 + 21390625 = 7634^2 + 4625^2 .

It is an emirp because it is prime and its reverse (18586697) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79668581 - 2⁶ = 79668517 is a prime.

It is a super-2 number, since 2×79668581² = 12694165597107122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79668521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39834290 + 39834291.

It is an arithmetic number, because the mean of its divisors is an integer number (39834291).

Almost surely, 2^79668581 is an apocalyptic number.

It is an amenable number.

79668581 is a deficient number, since it is larger than the sum of its proper divisors (1).

79668581 is an equidigital number, since it uses as much as digits as its factorization.

79668581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 50.

The square root of 79668581 is about 8925.7257968190. The cubic root of 79668581 is about 430.2910972846.

The spelling of 79668581 in words is "seventy-nine million, six hundred sixty-eight thousand, five hundred eighty-one".