399440432169 has 9 divisors (see below), whose sum is σ = 576972251869. Its totient is φ = 266292357420.

The previous prime is 399440432147. The next prime is 399440432177. The reversal of 399440432169 is 961234044993.

The square root of 399440432169 is 632013.

It is a perfect power (a square), and thus also a powerful number.

399440432169 is a `hidden beast` number, since 3 + 9 + 9 + 4 + 40 + 432 + 169 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 399440432169 - 2³⁵ = 365080693801 is a prime.

It is a super-2 number, since 2×399440432169² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399440432129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1790704 + ... + 2001374.

Almost surely, 2^399440432169 is an apocalyptic number.

399440432169 is the 632013-rd square number.

399440432169 is the 316007-th centered octagonal number.

It is an amenable number.

399440432169 is a deficient number, since it is larger than the sum of its proper divisors (177531819700).

399440432169 is an frugal number, since it uses more digits than its factorization.

399440432169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421348 (or 210674 counting only the distinct ones).

The product of its (nonzero) digits is 5038848, while the sum is 54.

The spelling of 399440432169 in words is "three hundred ninety-nine billion, four hundred forty million, four hundred thirty-two thousand, one hundred sixty-nine".