399240321 has 4 divisors (see below), whose sum is σ = 532320432. Its totient is φ = 266160212.

The previous prime is 399240311. The next prime is 399240353. The reversal of 399240321 is 123042993.

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 a de Polignac number, because none of the positive numbers 2^k-399240321 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399240311) 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, 66540051 + ... + 66540056.

It is an arithmetic number, because the mean of its divisors is an integer number (133080108).

Almost surely, 2^399240321 is an apocalyptic number.

It is an amenable number.

399240321 is a deficient number, since it is larger than the sum of its proper divisors (133080111).

399240321 is a wasteful number, since it uses less digits than its factorization.

399240321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133080110.

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 399240321 is about 19980.9989990491. The cubic root of 399240321 is about 736.3395572304.

The spelling of 399240321 in words is "three hundred ninety-nine million, two hundred forty thousand, three hundred twenty-one".