399768947 has 2 divisors, whose sum is σ = 399768948. Its totient is φ = 399768946.

The previous prime is 399768917. The next prime is 399768961. The reversal of 399768947 is 749867993.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399768947 - 2²² = 395574643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 399768947.

It is not a weakly prime, because it can be changed into another prime (399768917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199884473 + 199884474.

It is an arithmetic number, because the mean of its divisors is an integer number (199884474).

Almost surely, 2^399768947 is an apocalyptic number.

399768947 is a deficient number, since it is larger than the sum of its proper divisors (1).

399768947 is an equidigital number, since it uses as much as digits as its factorization.

399768947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20575296, while the sum is 62.

The square root of 399768947 is about 19994.2228406107. Note that the first 3 decimals coincide. The cubic root of 399768947 is about 736.6644046485.

The spelling of 399768947 in words is "three hundred ninety-nine million, seven hundred sixty-eight thousand, nine hundred forty-seven".