79964445581 has 2 divisors, whose sum is σ = 79964445582. Its totient is φ = 79964445580.

The previous prime is 79964445553. The next prime is 79964445599. The reversal of 79964445581 is 18554446997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78540062500 + 1424383081 = 280250^2 + 37741^2 .

It is an emirp because it is prime and its reverse (18554446997) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-79964445581 is a prime.

It is a super-2 number, since 2×79964445581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79964445511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39982222790 + 39982222791.

It is an arithmetic number, because the mean of its divisors is an integer number (39982222791).

Almost surely, 2^79964445581 is an apocalyptic number.

It is an amenable number.

79964445581 is a deficient number, since it is larger than the sum of its proper divisors (1).

79964445581 is an equidigital number, since it uses as much as digits as its factorization.

79964445581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43545600, while the sum is 62.

The spelling of 79964445581 in words is "seventy-nine billion, nine hundred sixty-four million, four hundred forty-five thousand, five hundred eighty-one".