79779661 has 8 divisors (see below), whose sum is σ = 86427320. Its totient is φ = 73640736.

The previous prime is 79779653. The next prime is 79779673. The reversal of 79779661 is 16697797.

It can be written as a sum of positive squares in 4 ways, for example, as 40717161 + 39062500 = 6381^2 + 6250^2 .

It is not a de Polignac number, because 79779661 - 2³ = 79779653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 79779599 and 79779608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79779611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15960 + ... + 20353.

It is an arithmetic number, because the mean of its divisors is an integer number (10803415).

Almost surely, 2^79779661 is an apocalyptic number.

It is an amenable number.

79779661 is a deficient number, since it is larger than the sum of its proper divisors (6647659).

79779661 is an equidigital number, since it uses as much as digits as its factorization.

79779661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36352 (or 36326 counting only the distinct ones).

The product of its digits is 1000188, while the sum is 52.

The square root of 79779661 is about 8931.9460925377. The cubic root of 79779661 is about 430.4909859473.

The spelling of 79779661 in words is "seventy-nine million, seven hundred seventy-nine thousand, six hundred sixty-one".