399683381 has 2 divisors, whose sum is σ = 399683382. Its totient is φ = 399683380.

The previous prime is 399683327. The next prime is 399683387. The reversal of 399683381 is 183386993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 245079025 + 154604356 = 15655^2 + 12434^2 .

It is a cyclic number.

It is not a de Polignac number, because 399683381 - 2²² = 395489077 is a prime.

It is a super-2 number, since 2×399683381² = 319493610095182322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399683387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199841690 + 199841691.

It is an arithmetic number, because the mean of its divisors is an integer number (199841691).

Almost surely, 2^399683381 is an apocalyptic number.

It is an amenable number.

399683381 is a deficient number, since it is larger than the sum of its proper divisors (1).

399683381 is an equidigital number, since it uses as much as digits as its factorization.

399683381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 839808, while the sum is 50.

The square root of 399683381 is about 19992.0829580112. The cubic root of 399683381 is about 736.6118426835.

The spelling of 399683381 in words is "three hundred ninety-nine million, six hundred eighty-three thousand, three hundred eighty-one".