394636621 has 2 divisors, whose sum is σ = 394636622. Its totient is φ = 394636620.

The previous prime is 394636609. The next prime is 394636699. The reversal of 394636621 is 126636493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 392475721 + 2160900 = 19811^2 + 1470^2 .

It is a cyclic number.

It is not a de Polignac number, because 394636621 - 2⁷ = 394636493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394636601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197318310 + 197318311.

It is an arithmetic number, because the mean of its divisors is an integer number (197318311).

Almost surely, 2^394636621 is an apocalyptic number.

It is an amenable number.

394636621 is a deficient number, since it is larger than the sum of its proper divisors (1).

394636621 is an equidigital number, since it uses as much as digits as its factorization.

394636621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 40.

The square root of 394636621 is about 19865.4630200255. The cubic root of 394636621 is about 733.4983275901.

The spelling of 394636621 in words is "three hundred ninety-four million, six hundred thirty-six thousand, six hundred twenty-one".