398681 has 2 divisors, whose sum is σ = 398682. Its totient is φ = 398680.

The previous prime is 398669. The next prime is 398683. The reversal of 398681 is 186893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 225625 + 173056 = 475^2 + 416^2 .

It is a cyclic number.

It is not a de Polignac number, because 398681 - 2¹⁸ = 136537 is a prime.

It is a super-2 number, since 2×398681² = 317893079522, which contains 22 as substring.

Together with 398683, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 9.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 398681.

It is not a weakly prime, because it can be changed into another prime (398683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199340 + 199341.

It is an arithmetic number, because the mean of its divisors is an integer number (199341).

2³⁹⁸⁶⁸¹ is an apocalyptic number.

It is an amenable number.

398681 is a deficient number, since it is larger than the sum of its proper divisors (1).

398681 is an equidigital number, since it uses as much as digits as its factorization.

398681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 35.

The square root of 398681 is about 631.4119099289. The cubic root of 398681 is about 73.5995534984.

The spelling of 398681 in words is "three hundred ninety-eight thousand, six hundred eighty-one".