394904689 has 2 divisors, whose sum is σ = 394904690. Its totient is φ = 394904688.

The previous prime is 394904681. The next prime is 394904693. The reversal of 394904689 is 986409493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 236144689 + 158760000 = 15367^2 + 12600^2 .

It is an emirp because it is prime and its reverse (986409493) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 394904689 - 2³ = 394904681 is a prime.

It is not a weakly prime, because it can be changed into another prime (394904681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197452344 + 197452345.

It is an arithmetic number, because the mean of its divisors is an integer number (197452345).

Almost surely, 2^394904689 is an apocalyptic number.

It is an amenable number.

394904689 is a deficient number, since it is larger than the sum of its proper divisors (1).

394904689 is an equidigital number, since it uses as much as digits as its factorization.

394904689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1679616, while the sum is 52.

The square root of 394904689 is about 19872.2089612604. The cubic root of 394904689 is about 733.6643731068.

It can be divided in two parts, 394904 and 689, that added together give a palindrome (395593).

The spelling of 394904689 in words is "three hundred ninety-four million, nine hundred four thousand, six hundred eighty-nine".