399830891 has 4 divisors (see below), whose sum is σ = 405462384. Its totient is φ = 394199400.

The previous prime is 399830807. The next prime is 399830897. The reversal of 399830891 is 198038993.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 399830891 - 2¹⁸ = 399568747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399830897) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2815640 + ... + 2815781.

It is an arithmetic number, because the mean of its divisors is an integer number (101365596).

Almost surely, 2^399830891 is an apocalyptic number.

399830891 is a deficient number, since it is larger than the sum of its proper divisors (5631493).

399830891 is an equidigital number, since it uses as much as digits as its factorization.

399830891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5631492.

The product of its (nonzero) digits is 419904, while the sum is 50.

The square root of 399830891 is about 19995.7718280641. The cubic root of 399830891 is about 736.7024512782.

The spelling of 399830891 in words is "three hundred ninety-nine million, eight hundred thirty thousand, eight hundred ninety-one".