399300991 has 4 divisors (see below), whose sum is σ = 402173800. Its totient is φ = 396428184.

The previous prime is 399300961. The next prime is 399301031. The reversal of 399300991 is 199003993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199003993 = 1373 ⋅144941.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399300991 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 (399300961) 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, 1436196 + ... + 1436473.

It is an arithmetic number, because the mean of its divisors is an integer number (100543450).

Almost surely, 2^399300991 is an apocalyptic number.

399300991 is a deficient number, since it is larger than the sum of its proper divisors (2872809).

399300991 is a wasteful number, since it uses less digits than its factorization.

399300991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2872808.

The product of its (nonzero) digits is 59049, while the sum is 43.

The square root of 399300991 is about 19982.5171337347. The cubic root of 399300991 is about 736.3768542800.

The spelling of 399300991 in words is "three hundred ninety-nine million, three hundred thousand, nine hundred ninety-one".