398387640 has 128 divisors (see below), whose sum is σ = 1393920000. Its totient is φ = 91050624.

The previous prime is 398387629. The next prime is 398387659. The reversal of 398387640 is 46783893.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 398387640.

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 31 ways as a sum of consecutive naturals, for example, 36321 + ... + 45999.

It is an arithmetic number, because the mean of its divisors is an integer number (10890000).

Almost surely, 2^398387640 is an apocalyptic number.

398387640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 398387640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (696960000).

398387640 is an abundant number, since it is smaller than the sum of its proper divisors (995532360).

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

398387640 is a wasteful number, since it uses less digits than its factorization.

398387640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9714 (or 9696 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 48.

The square root of 398387640 is about 19959.6502975378. The cubic root of 398387640 is about 735.8149690431.

The spelling of 398387640 in words is "three hundred ninety-eight million, three hundred eighty-seven thousand, six hundred forty".