394669621 has 4 divisors (see below), whose sum is σ = 394743244. Its totient is φ = 394596000.

The previous prime is 394669589. The next prime is 394669633. The reversal of 394669621 is 126966493.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126966493 = 19 ⋅6682447.

It can be written as a sum of positive squares in 2 ways, for example, as 275095396 + 119574225 = 16586^2 + 10935^2 .

It is a cyclic number.

It is not a de Polignac number, because 394669621 - 2⁵ = 394669589 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 (394669661) 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, 28080 + ... + 39721.

It is an arithmetic number, because the mean of its divisors is an integer number (98685811).

Almost surely, 2^394669621 is an apocalyptic number.

It is an amenable number.

394669621 is a deficient number, since it is larger than the sum of its proper divisors (73623).

394669621 is an equidigital number, since it uses as much as digits as its factorization.

394669621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73622.

The product of its digits is 419904, while the sum is 46.

The square root of 394669621 is about 19866.2935898974. The cubic root of 394669621 is about 733.5187723646.

The spelling of 394669621 in words is "three hundred ninety-four million, six hundred sixty-nine thousand, six hundred twenty-one".