79879861 has 2 divisors, whose sum is σ = 79879862. Its totient is φ = 79879860.

The previous prime is 79879859. The next prime is 79879871. The reversal of 79879861 is 16897897.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71064900 + 8814961 = 8430^2 + 2969^2 .

It is a cyclic number.

It is not a de Polignac number, because 79879861 - 2¹ = 79879859 is a prime.

Together with 79879859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79879801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39939930 + 39939931.

It is an arithmetic number, because the mean of its divisors is an integer number (39939931).

Almost surely, 2^79879861 is an apocalyptic number.

It is an amenable number.

79879861 is a deficient number, since it is larger than the sum of its proper divisors (1).

79879861 is an equidigital number, since it uses as much as digits as its factorization.

79879861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 55.

The square root of 79879861 is about 8937.5534124278. The cubic root of 79879861 is about 430.6711369204.

The spelling of 79879861 in words is "seventy-nine million, eight hundred seventy-nine thousand, eight hundred sixty-one".