399442469 has 2 divisors, whose sum is σ = 399442470. Its totient is φ = 399442468.

The previous prime is 399442451. The next prime is 399442487. The reversal of 399442469 is 964244993.

It is a balanced prime because it is at equal distance from previous prime (399442451) and next prime (399442487).

It can be written as a sum of positive squares in only one way, i.e., 338008225 + 61434244 = 18385^2 + 7838^2 .

It is a cyclic number.

It is not a de Polignac number, because 399442469 - 2¹⁶ = 399376933 is a prime.

It is a super-2 number, since 2×399442469² = 319108572081631922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399442499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199721234 + 199721235.

It is an arithmetic number, because the mean of its divisors is an integer number (199721235).

Almost surely, 2^399442469 is an apocalyptic number.

It is an amenable number.

399442469 is a deficient number, since it is larger than the sum of its proper divisors (1).

399442469 is an equidigital number, since it uses as much as digits as its factorization.

399442469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 50.

The square root of 399442469 is about 19986.0568647245. The cubic root of 399442469 is about 736.4638135956.

The spelling of 399442469 in words is "three hundred ninety-nine million, four hundred forty-two thousand, four hundred sixty-nine".