399141921 has 4 divisors (see below), whose sum is σ = 532189232. Its totient is φ = 266094612.

The previous prime is 399141913. The next prime is 399141943. The reversal of 399141921 is 129141993.

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.

It is not a de Polignac number, because 399141921 - 2³ = 399141913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 399141921.

It is not an unprimeable number, because it can be changed into a prime (399141901) 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, 66523651 + ... + 66523656.

It is an arithmetic number, because the mean of its divisors is an integer number (133047308).

Almost surely, 2^399141921 is an apocalyptic number.

It is an amenable number.

399141921 is a deficient number, since it is larger than the sum of its proper divisors (133047311).

399141921 is a wasteful number, since it uses less digits than its factorization.

399141921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133047310.

The product of its digits is 17496, while the sum is 39.

The square root of 399141921 is about 19978.5365079627. The cubic root of 399141921 is about 736.2790575246.

The spelling of 399141921 in words is "three hundred ninety-nine million, one hundred forty-one thousand, nine hundred twenty-one".