399366281 has 6 divisors (see below), whose sum is σ = 409238046. Its totient is φ = 389500800.

The previous prime is 399366269. The next prime is 399366287. The reversal of 399366281 is 182663993.

It can be written as a sum of positive squares in 3 ways, for example, as 146047225 + 253319056 = 12085^2 + 15916^2 .

It is not a de Polignac number, because 399366281 - 2¹⁰ = 399365257 is a prime.

It is a super-2 number, since 2×399366281² = 318986852799541922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399366287) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 126401 + ... + 129521.

It is an arithmetic number, because the mean of its divisors is an integer number (68206341).

Almost surely, 2^399366281 is an apocalyptic number.

It is an amenable number.

399366281 is a deficient number, since it is larger than the sum of its proper divisors (9871765).

399366281 is an frugal number, since it uses more digits than its factorization.

399366281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6283 (or 3162 counting only the distinct ones).

The product of its digits is 419904, while the sum is 47.

The square root of 399366281 is about 19984.1507450279. The cubic root of 399366281 is about 736.4169872672.

The spelling of 399366281 in words is "three hundred ninety-nine million, three hundred sixty-six thousand, two hundred eighty-one".