393979621 has 8 divisors (see below), whose sum is σ = 450472320. Its totient is φ = 337539408.

The previous prime is 393979601. The next prime is 393979633. The reversal of 393979621 is 126979393.

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 393979621 - 2⁹ = 393979109 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 (393979601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4560 + ... + 28438.

It is an arithmetic number, because the mean of its divisors is an integer number (56309040).

Almost surely, 2^393979621 is an apocalyptic number.

It is an amenable number.

393979621 is a deficient number, since it is larger than the sum of its proper divisors (56492699).

393979621 is a wasteful number, since it uses less digits than its factorization.

393979621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26243.

The product of its digits is 551124, while the sum is 49.

The square root of 393979621 is about 19848.9198950472. The cubic root of 393979621 is about 733.0910532742.

The spelling of 393979621 in words is "three hundred ninety-three million, nine hundred seventy-nine thousand, six hundred twenty-one".