393444621 has 10 divisors (see below), whose sum is σ = 587738382. Its totient is φ = 262296360.

The previous prime is 393444619. The next prime is 393444631. The reversal of 393444621 is 126444393.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 317231721 + 76212900 = 17811^2 + 8730^2 .

It is not a de Polignac number, because 393444621 - 2¹ = 393444619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393444631) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2428590 + ... + 2428751.

Almost surely, 2^393444621 is an apocalyptic number.

It is an amenable number.

393444621 is a deficient number, since it is larger than the sum of its proper divisors (194293761).

393444621 is an equidigital number, since it uses as much as digits as its factorization.

393444621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4857353 (or 4857344 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 393444621 is about 19835.4385129243. The cubic root of 393444621 is about 732.7590721631.

The spelling of 393444621 in words is "three hundred ninety-three million, four hundred forty-four thousand, six hundred twenty-one".