398021 has 8 divisors (see below), whose sum is σ = 454104. Its totient is φ = 345600.

The previous prime is 398011. The next prime is 398023. The reversal of 398021 is 120893.

398021 = 111² + 112² + ... + 136².

It can be written as a sum of positive squares in 4 ways, for example, as 7396 + 390625 = 86^2 + 625^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 398021 - 2¹⁰ = 396997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 680 + ... + 1121.

It is an arithmetic number, because the mean of its divisors is an integer number (56763).

2³⁹⁸⁰²¹ is an apocalyptic number.

It is an amenable number.

398021 is a deficient number, since it is larger than the sum of its proper divisors (56083).

398021 is a wasteful number, since it uses less digits than its factorization.

398021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1831.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 398021 is about 630.8890552229. The cubic root of 398021 is about 73.5589173883.

The spelling of 398021 in words is "three hundred ninety-eight thousand, twenty-one".