394709645221 has 2 divisors, whose sum is σ = 394709645222. Its totient is φ = 394709645220.

The previous prime is 394709645203. The next prime is 394709645333. The reversal of 394709645221 is 122546907493.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 393919416900 + 790228321 = 627630^2 + 28111^2 .

It is a cyclic number.

It is not a de Polignac number, because 394709645221 - 2²⁹ = 394172774309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394709345221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197354822610 + 197354822611.

It is an arithmetic number, because the mean of its divisors is an integer number (197354822611).

Almost surely, 2^394709645221 is an apocalyptic number.

It is an amenable number.

394709645221 is a deficient number, since it is larger than the sum of its proper divisors (1).

394709645221 is an equidigital number, since it uses as much as digits as its factorization.

394709645221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3265920, while the sum is 52.

The spelling of 394709645221 in words is "three hundred ninety-four billion, seven hundred nine million, six hundred forty-five thousand, two hundred twenty-one".