399259981 has 8 divisors (see below), whose sum is σ = 401068800. Its totient is φ = 397456080.

The previous prime is 399259979. The next prime is 399259997. The reversal of 399259981 is 189952993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399259981 - 2¹ = 399259979 is a prime.

It is a super-2 number, since 2×399259981² = 318817064856240722, 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 (399259951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 302040 + ... + 303358.

It is an arithmetic number, because the mean of its divisors is an integer number (50133600).

Almost surely, 2^399259981 is an apocalyptic number.

It is an amenable number.

399259981 is a deficient number, since it is larger than the sum of its proper divisors (1808819).

399259981 is a wasteful number, since it uses less digits than its factorization.

399259981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2459.

The product of its digits is 1574640, while the sum is 55.

The square root of 399259981 is about 19981.4909603863. The cubic root of 399259981 is about 736.3516436833.

The spelling of 399259981 in words is "three hundred ninety-nine million, two hundred fifty-nine thousand, nine hundred eighty-one".