399639421 has 8 divisors (see below), whose sum is σ = 417222720. Its totient is φ = 382073472.

The previous prime is 399639413. The next prime is 399639481. The reversal of 399639421 is 124936993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399639421 - 2³ = 399639413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399639481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70146 + ... + 75628.

It is an arithmetic number, because the mean of its divisors is an integer number (52152840).

Almost surely, 2^399639421 is an apocalyptic number.

It is an amenable number.

399639421 is a deficient number, since it is larger than the sum of its proper divisors (17583299).

399639421 is a wasteful number, since it uses less digits than its factorization.

399639421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8675.

The product of its digits is 314928, while the sum is 46.

The square root of 399639421 is about 19990.9834925648. The cubic root of 399639421 is about 736.5848357697.

The spelling of 399639421 in words is "three hundred ninety-nine million, six hundred thirty-nine thousand, four hundred twenty-one".