79899961 has 2 divisors, whose sum is σ = 79899962. Its totient is φ = 79899960.

The previous prime is 79899947. The next prime is 79899973. The reversal of 79899961 is 16999897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40398736 + 39501225 = 6356^2 + 6285^2 .

It is an emirp because it is prime and its reverse (16999897) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79899961 - 2⁵ = 79899929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 79899896 and 79899905.

It is not a weakly prime, because it can be changed into another prime (79899931) 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 as a sum of consecutive naturals, namely, 39949980 + 39949981.

It is an arithmetic number, because the mean of its divisors is an integer number (39949981).

Almost surely, 2^79899961 is an apocalyptic number.

It is an amenable number.

79899961 is a deficient number, since it is larger than the sum of its proper divisors (1).

79899961 is an equidigital number, since it uses as much as digits as its factorization.

79899961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2204496, while the sum is 58.

The square root of 79899961 is about 8938.6778105042. The cubic root of 79899961 is about 430.7072568459.

The spelling of 79899961 in words is "seventy-nine million, eight hundred ninety-nine thousand, nine hundred sixty-one".