398936891 has 2 divisors, whose sum is σ = 398936892. Its totient is φ = 398936890.

The previous prime is 398936831. The next prime is 398936911. The reversal of 398936891 is 198639893.

It is a strong prime.

It is an emirp because it is prime and its reverse (198639893) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398936891 is a prime.

It is not a weakly prime, because it can be changed into another prime (398936801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199468445 + 199468446.

It is an arithmetic number, because the mean of its divisors is an integer number (199468446).

Almost surely, 2^398936891 is an apocalyptic number.

398936891 is a deficient number, since it is larger than the sum of its proper divisors (1).

398936891 is an equidigital number, since it uses as much as digits as its factorization.

398936891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2519424, while the sum is 56.

The square root of 398936891 is about 19973.4045921070. The cubic root of 398936891 is about 736.1529660746.

The spelling of 398936891 in words is "three hundred ninety-eight million, nine hundred thirty-six thousand, eight hundred ninety-one".