399281 has 2 divisors, whose sum is σ = 399282. Its totient is φ = 399280.

The previous prime is 399277. The next prime is 399283. The reversal of 399281 is 182993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 270400 + 128881 = 520^2 + 359^2 .

It is a cyclic number.

It is not a de Polignac number, because 399281 - 2² = 399277 is a prime.

It is a super-2 number, since 2×399281² = 318850633922, which contains 22 as substring.

Together with 399283, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199640 + 199641.

It is an arithmetic number, because the mean of its divisors is an integer number (199641).

2³⁹⁹²⁸¹ is an apocalyptic number.

It is an amenable number.

399281 is a deficient number, since it is larger than the sum of its proper divisors (1).

399281 is an equidigital number, since it uses as much as digits as its factorization.

399281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 32.

The square root of 399281 is about 631.8868569610. The cubic root of 399281 is about 73.6364565175.

The spelling of 399281 in words is "three hundred ninety-nine thousand, two hundred eighty-one".