398618640 has 240 divisors, whose sum is σ = 1543651200. Its totient is φ = 90298368.

The previous prime is 398618639. The next prime is 398618699. The reversal of 398618640 is 46816893.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 700276 + ... + 700844.

It is an arithmetic number, because the mean of its divisors is an integer number (6431880).

Almost surely, 2^398618640 is an apocalyptic number.

398618640 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 398618640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (771825600).

398618640 is an abundant number, since it is smaller than the sum of its proper divisors (1145032560).

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

398618640 is a wasteful number, since it uses less digits than its factorization.

398618640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 734 (or 725 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 398618640 is about 19965.4361334783. The cubic root of 398618640 is about 735.9571592109.

The spelling of 398618640 in words is "three hundred ninety-eight million, six hundred eighteen thousand, six hundred forty".