393989 has 2 divisors, whose sum is σ = 393990. Its totient is φ = 393988.

The previous prime is 393977. The next prime is 393997. The reversal of 393989 is 989393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 390625 + 3364 = 625^2 + 58^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393989 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (393919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196994 + 196995.

It is an arithmetic number, because the mean of its divisors is an integer number (196995).

2³⁹³⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

393989 is a deficient number, since it is larger than the sum of its proper divisors (1).

393989 is an equidigital number, since it uses as much as digits as its factorization.

393989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52488, while the sum is 41.

The square root of 393989 is about 627.6854307693. The cubic root of 393989 is about 73.3096870501.

The spelling of 393989 in words is "three hundred ninety-three thousand, nine hundred eighty-nine".