399939621 has 8 divisors (see below), whose sum is σ = 533624160. Its totient is φ = 266440752.

The previous prime is 399939577. The next prime is 399939647. The reversal of 399939621 is 126939993.

It is a happy number.

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

It is not a de Polignac number, because 399939621 - 2¹⁸ = 399677477 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399939821) 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, 41310 + ... + 50063.

It is an arithmetic number, because the mean of its divisors is an integer number (66703020).

Almost surely, 2^399939621 is an apocalyptic number.

It is an amenable number.

399939621 is a deficient number, since it is larger than the sum of its proper divisors (133684539).

399939621 is a wasteful number, since it uses less digits than its factorization.

399939621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92835.

The product of its digits is 708588, while the sum is 51.

The square root of 399939621 is about 19998.4904680328. The cubic root of 399939621 is about 736.7692248396.

The spelling of 399939621 in words is "three hundred ninety-nine million, nine hundred thirty-nine thousand, six hundred twenty-one".