79878961 has 2 divisors, whose sum is σ = 79878962. Its totient is φ = 79878960.

The previous prime is 79878959. The next prime is 79878973. The reversal of 79878961 is 16987897.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77176225 + 2702736 = 8785^2 + 1644^2 .

It is a cyclic number.

It is not a de Polignac number, because 79878961 - 2¹ = 79878959 is a prime.

Together with 79878959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (79878901) 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, 39939480 + 39939481.

It is an arithmetic number, because the mean of its divisors is an integer number (39939481).

Almost surely, 2^79878961 is an apocalyptic number.

It is an amenable number.

79878961 is a deficient number, since it is larger than the sum of its proper divisors (1).

79878961 is an equidigital number, since it uses as much as digits as its factorization.

79878961 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 79878961 is about 8937.5030629365. The cubic root of 79878961 is about 430.6695194686.

It can be divided in two parts, 7987896 and 1, that added together give a palindrome (7987897).

The spelling of 79878961 in words is "seventy-nine million, eight hundred seventy-eight thousand, nine hundred sixty-one".