399732991 has 8 divisors (see below), whose sum is σ = 457324704. Its totient is φ = 342263040.

The previous prime is 399732967. The next prime is 399733051. The reversal of 399732991 is 199237993.

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

It is not a de Polignac number, because 399732991 - 2⁷ = 399732863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399732901) 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, 23290 + ... + 36631.

It is an arithmetic number, because the mean of its divisors is an integer number (57165588).

Almost surely, 2^399732991 is an apocalyptic number.

399732991 is a deficient number, since it is larger than the sum of its proper divisors (57591713).

399732991 is an equidigital number, since it uses as much as digits as its factorization.

399732991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60881.

The product of its digits is 826686, while the sum is 52.

The square root of 399732991 is about 19993.3236606623. The cubic root of 399732991 is about 736.6423183078.

The spelling of 399732991 in words is "three hundred ninety-nine million, seven hundred thirty-two thousand, nine hundred ninety-one".