399565469 has 2 divisors, whose sum is σ = 399565470. Its totient is φ = 399565468.

The previous prime is 399565457. The next prime is 399565513. The reversal of 399565469 is 964565993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 338928100 + 60637369 = 18410^2 + 7787^2 .

It is an emirp because it is prime and its reverse (964565993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399565469 - 2¹² = 399561373 is a prime.

It is a super-2 number, since 2×399565469² = 319305128034379922, 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 (399565429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199782734 + 199782735.

It is an arithmetic number, because the mean of its divisors is an integer number (199782735).

Almost surely, 2^399565469 is an apocalyptic number.

It is an amenable number.

399565469 is a deficient number, since it is larger than the sum of its proper divisors (1).

399565469 is an equidigital number, since it uses as much as digits as its factorization.

399565469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7873200, while the sum is 56.

The square root of 399565469 is about 19989.1337731278. The cubic root of 399565469 is about 736.5393987423.

The spelling of 399565469 in words is "three hundred ninety-nine million, five hundred sixty-five thousand, four hundred sixty-nine".