398390840 has 32 divisors (see below), whose sum is σ = 920609280. Its totient is φ = 155048832.

The previous prime is 398390831. The next prime is 398390851. The reversal of 398390840 is 48093893.

It is a super-2 number, since 2×398390840² = 317430522791811200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 398390791 and 398390800.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133112 + ... + 136071.

It is an arithmetic number, because the mean of its divisors is an integer number (28769040).

Almost surely, 2^398390840 is an apocalyptic number.

It is an amenable number.

398390840 is an abundant number, since it is smaller than the sum of its proper divisors (522218440).

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

398390840 is a wasteful number, since it uses less digits than its factorization.

398390840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269231 (or 269227 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 398390840 is about 19959.7304591019. The cubic root of 398390840 is about 735.8169391524.

The spelling of 398390840 in words is "three hundred ninety-eight million, three hundred ninety thousand, eight hundred forty".