399766879 has 2 divisors, whose sum is σ = 399766880. Its totient is φ = 399766878.

The previous prime is 399766877. The next prime is 399766889. The reversal of 399766879 is 978667993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399766879 - 2¹ = 399766877 is a prime.

Together with 399766877, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 399766879.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399766877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199883439 + 199883440.

It is an arithmetic number, because the mean of its divisors is an integer number (199883440).

Almost surely, 2^399766879 is an apocalyptic number.

399766879 is a deficient number, since it is larger than the sum of its proper divisors (1).

399766879 is an equidigital number, since it uses as much as digits as its factorization.

399766879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30862944, while the sum is 64.

The square root of 399766879 is about 19994.1711256056. The cubic root of 399766879 is about 736.6631343943.

It can be divided in two parts, 3997 and 66879, that added together give a triangular number (70876 = T₃₇₆).

The spelling of 399766879 in words is "three hundred ninety-nine million, seven hundred sixty-six thousand, eight hundred seventy-nine".