398987 has 4 divisors (see below), whose sum is σ = 403560. Its totient is φ = 394416.

The previous prime is 398977. The next prime is 398989. The reversal of 398987 is 789893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789893 = 13 ⋅60761.

It is a cyclic number.

It is not a de Polignac number, because 398987 - 2⁸ = 398731 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 398987.

It is not an unprimeable number, because it can be changed into a prime (398989) 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, 2153 + ... + 2330.

It is an arithmetic number, because the mean of its divisors is an integer number (100890).

2³⁹⁸⁹⁸⁷ is an apocalyptic number.

398987 is a deficient number, since it is larger than the sum of its proper divisors (4573).

398987 is an equidigital number, since it uses as much as digits as its factorization.

398987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4572.

The product of its digits is 108864, while the sum is 44.

The square root of 398987 is about 631.6541775370. The cubic root of 398987 is about 73.6183786609.

The spelling of 398987 in words is "three hundred ninety-eight thousand, nine hundred eighty-seven".