393937381 has 2 divisors, whose sum is σ = 393937382. Its totient is φ = 393937380.

The previous prime is 393937373. The next prime is 393937387. The reversal of 393937381 is 183739393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 237437281 + 156500100 = 15409^2 + 12510^2 .

It is a cyclic number.

It is not a de Polignac number, because 393937381 - 2³ = 393937373 is a prime.

It is a super-2 number, since 2×393937381² = 310373320298278322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (393937387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196968690 + 196968691.

It is an arithmetic number, because the mean of its divisors is an integer number (196968691).

Almost surely, 2^393937381 is an apocalyptic number.

It is an amenable number.

393937381 is a deficient number, since it is larger than the sum of its proper divisors (1).

393937381 is an equidigital number, since it uses as much as digits as its factorization.

393937381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 46.

The square root of 393937381 is about 19847.8558287791. The cubic root of 393937381 is about 733.0648532111.

The spelling of 393937381 in words is "three hundred ninety-three million, nine hundred thirty-seven thousand, three hundred eighty-one".