399240387 has 96 divisors (see below), whose sum is σ = 750758400. Its totient is φ = 207821376.

The previous prime is 399240353. The next prime is 399240389. The reversal of 399240387 is 783042993.

It is a happy number.

It is not a de Polignac number, because 399240387 - 2¹¹ = 399238339 is a prime.

It is a super-2 number, since 2×399240387² = 318785773223819538, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (399240389) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2390578 + ... + 2390744.

It is an arithmetic number, because the mean of its divisors is an integer number (7820400).

Almost surely, 2^399240387 is an apocalyptic number.

399240387 is a deficient number, since it is larger than the sum of its proper divisors (351518013).

399240387 is a wasteful number, since it uses less digits than its factorization.

399240387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The square root of 399240387 is about 19981.0006506181. Note that the first 3 decimals coincide. The cubic root of 399240387 is about 736.3395978061.

The spelling of 399240387 in words is "three hundred ninety-nine million, two hundred forty thousand, three hundred eighty-seven".