399782969 has 2 divisors, whose sum is σ = 399782970. Its totient is φ = 399782968.

The previous prime is 399782921. The next prime is 399782983. The reversal of 399782969 is 969287993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 320839744 + 78943225 = 17912^2 + 8885^2 .

It is an emirp because it is prime and its reverse (969287993) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399782969 is a prime.

It is a super-2 number, since 2×399782969² = 319652844604909922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (399782269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199891484 + 199891485.

It is an arithmetic number, because the mean of its divisors is an integer number (199891485).

Almost surely, 2^399782969 is an apocalyptic number.

It is an amenable number.

399782969 is a deficient number, since it is larger than the sum of its proper divisors (1).

399782969 is an equidigital number, since it uses as much as digits as its factorization.

399782969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13226976, while the sum is 62.

The square root of 399782969 is about 19994.5734888244. The cubic root of 399782969 is about 736.6730174465.

The spelling of 399782969 in words is "three hundred ninety-nine million, seven hundred eighty-two thousand, nine hundred sixty-nine".