398731 has 2 divisors, whose sum is σ = 398732. Its totient is φ = 398730.

The previous prime is 398729. The next prime is 398759. The reversal of 398731 is 137893.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 398731 - 2¹ = 398729 is a prime.

It is a super-2 number, since 2×398731² = 317972820722, which contains 22 as substring.

Together with 398729, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 398693 and 398702.

It is not a weakly prime, because it can be changed into another prime (398711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199365 + 199366.

It is an arithmetic number, because the mean of its divisors is an integer number (199366).

2³⁹⁸⁷³¹ is an apocalyptic number.

398731 is a deficient number, since it is larger than the sum of its proper divisors (1).

398731 is an equidigital number, since it uses as much as digits as its factorization.

398731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 31.

The square root of 398731 is about 631.4515024925. The cubic root of 398731 is about 73.6026301636.

The spelling of 398731 in words is "three hundred ninety-eight thousand, seven hundred thirty-one".