399771913 has 4 divisors (see below), whose sum is σ = 420812560. Its totient is φ = 378731268.

The previous prime is 399771863. The next prime is 399771919. The reversal of 399771913 is 319177993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 319177993 = 2467 ⋅129379.

It is a cyclic number.

It is not a de Polignac number, because 399771913 - 2⁹ = 399771401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399771919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10520295 + ... + 10520332.

It is an arithmetic number, because the mean of its divisors is an integer number (105203140).

Almost surely, 2^399771913 is an apocalyptic number.

It is an amenable number.

399771913 is a deficient number, since it is larger than the sum of its proper divisors (21040647).

399771913 is a wasteful number, since it uses less digits than its factorization.

399771913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21040646.

The product of its digits is 321489, while the sum is 49.

The square root of 399771913 is about 19994.2970118982. The cubic root of 399771913 is about 736.6662264852. Note that the first 3 decimals are identical.

The spelling of 399771913 in words is "three hundred ninety-nine million, seven hundred seventy-one thousand, nine hundred thirteen".