398731897 has 4 divisors (see below), whose sum is σ = 401408100. Its totient is φ = 396055696.

The previous prime is 398731873. The next prime is 398731903. The reversal of 398731897 is 798137893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 798137893 = 7 ⋅114019699.

It can be written as a sum of positive squares in 2 ways, for example, as 116122176 + 282609721 = 10776^2 + 16811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-398731897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398731097) 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, 1337878 + ... + 1338175.

It is an arithmetic number, because the mean of its divisors is an integer number (100352025).

Almost surely, 2^398731897 is an apocalyptic number.

It is an amenable number.

398731897 is a deficient number, since it is larger than the sum of its proper divisors (2676203).

398731897 is a wasteful number, since it uses less digits than its factorization.

398731897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2676202.

The product of its digits is 2286144, while the sum is 55.

The square root of 398731897 is about 19968.2722587609. The cubic root of 398731897 is about 736.0268535659.

The spelling of 398731897 in words is "three hundred ninety-eight million, seven hundred thirty-one thousand, eight hundred ninety-seven".