399082921 has 4 divisors (see below), whose sum is σ = 400493392. Its totient is φ = 397672452.

The previous prime is 399082907. The next prime is 399082927. The reversal of 399082921 is 129280993.

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 a cyclic number.

It is not a de Polignac number, because 399082921 - 2⁷ = 399082793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399082927) 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, 704811 + ... + 705376.

It is an arithmetic number, because the mean of its divisors is an integer number (100123348).

Almost surely, 2^399082921 is an apocalyptic number.

It is an amenable number.

399082921 is a deficient number, since it is larger than the sum of its proper divisors (1410471).

399082921 is a wasteful number, since it uses less digits than its factorization.

399082921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1410470.

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 399082921 is about 19977.0598687595. The cubic root of 399082921 is about 736.2427775260.

The spelling of 399082921 in words is "three hundred ninety-nine million, eighty-two thousand, nine hundred twenty-one".