399919321 has 2 divisors, whose sum is σ = 399919322. Its totient is φ = 399919320.

The previous prime is 399919301. The next prime is 399919327. The reversal of 399919321 is 123919993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 367872400 + 32046921 = 19180^2 + 5661^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399919321 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399919327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199959660 + 199959661.

It is an arithmetic number, because the mean of its divisors is an integer number (199959661).

Almost surely, 2^399919321 is an apocalyptic number.

It is an amenable number.

399919321 is a deficient number, since it is larger than the sum of its proper divisors (1).

399919321 is an equidigital number, since it uses as much as digits as its factorization.

399919321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 118098, while the sum is 46.

The square root of 399919321 is about 19997.9829232850. The cubic root of 399919321 is about 736.7567590676.

The spelling of 399919321 in words is "three hundred ninety-nine million, nine hundred nineteen thousand, three hundred twenty-one".