399533975569 has 3 divisors (see below), whose sum is σ = 399534607657. Its totient is φ = 399533343482.

The previous prime is 399533975549. The next prime is 399533975573. The reversal of 399533975569 is 965579335993.

The square root of 399533975569 is 632087.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 965579335993 = 8147 ⋅118519619.

It is not a de Polignac number, because 399533975569 - 2¹⁹ = 399533451281 is a prime.

It is a super-2 number, since 2×399533975569² (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 (399533975539) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 316044 + ... + 948130.

Almost surely, 2^399533975569 is an apocalyptic number.

399533975569 is the 632087-th square number.

399533975569 is the 316044-th centered octagonal number.

It is an amenable number.

399533975569 is a deficient number, since it is larger than the sum of its proper divisors (632088).

399533975569 is an frugal number, since it uses more digits than its factorization.

399533975569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1264174 (or 632087 counting only the distinct ones).

The product of its digits is 930021750, while the sum is 73.

The spelling of 399533975569 in words is "three hundred ninety-nine billion, five hundred thirty-three million, nine hundred seventy-five thousand, five hundred sixty-nine".