394991775359989 has 2 divisors, whose sum is σ = 394991775359990. Its totient is φ = 394991775359988.

The previous prime is 394991775359971. The next prime is 394991775360001. The reversal of 394991775359989 is 989953577199493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 332408376484900 + 62583398875089 = 18232070^2 + 7910967^2 .

It is a cyclic number.

It is not a de Polignac number, because 394991775359989 - 2⁵ = 394991775359957 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 394991775359989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394991775359969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197495887679994 + 197495887679995.

It is an arithmetic number, because the mean of its divisors is an integer number (197495887679995).

Almost surely, 2^{394991775359989} is an apocalyptic number.

It is an amenable number.

394991775359989 is a deficient number, since it is larger than the sum of its proper divisors (1).

394991775359989 is an equidigital number, since it uses as much as digits as its factorization.

394991775359989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 187492384800, while the sum is 97.

The spelling of 394991775359989 in words is "three hundred ninety-four trillion, nine hundred ninety-one billion, seven hundred seventy-five million, three hundred fifty-nine thousand, nine hundred eighty-nine".