393961331 has 2 divisors, whose sum is σ = 393961332. Its totient is φ = 393961330.

The previous prime is 393961289. The next prime is 393961343. The reversal of 393961331 is 133169393.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393961331 is a prime.

It is a super-2 number, since 2×393961331² = 310411060646583122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (393961531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196980665 + 196980666.

It is an arithmetic number, because the mean of its divisors is an integer number (196980666).

Almost surely, 2^393961331 is an apocalyptic number.

393961331 is a deficient number, since it is larger than the sum of its proper divisors (1).

393961331 is an equidigital number, since it uses as much as digits as its factorization.

393961331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39366, while the sum is 38.

The square root of 393961331 is about 19848.4591593403. The cubic root of 393961331 is about 733.0797088272.

The spelling of 393961331 in words is "three hundred ninety-three million, nine hundred sixty-one thousand, three hundred thirty-one".