398440 has 32 divisors (see below), whose sum is σ = 1025280. Its totient is φ = 136512.

The previous prime is 398423. The next prime is 398441. The reversal of 398440 is 44893.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 398399 and 398408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398441) by changing a digit.

398440 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 432 + ... + 991.

It is an arithmetic number, because the mean of its divisors is an integer number (32040).

2³⁹⁸⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

398440 is an abundant number, since it is smaller than the sum of its proper divisors (626840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

398440 is a wasteful number, since it uses less digits than its factorization.

398440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1441 (or 1437 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 398440 is about 631.2210389396. The cubic root of 398440 is about 73.5847203631.

It can be divided in two parts, 398 and 440, that added together give a palindrome (838).

The spelling of 398440 in words is "three hundred ninety-eight thousand, four hundred forty".