398840400 has 720 divisors, whose sum is σ = 1798992000. Its totient is φ = 81285120.

The previous prime is 398840399. The next prime is 398840459. The reversal of 398840400 is 4048893.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 20991591 + ... + 20991609.

It is an arithmetic number, because the mean of its divisors is an integer number (2498600).

Almost surely, 2^398840400 is an apocalyptic number.

398840400 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 398840400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (899496000).

398840400 is an abundant number, since it is smaller than the sum of its proper divisors (1400151600).

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

398840400 is a wasteful number, since it uses less digits than its factorization.

398840400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 398840400 is about 19970.9889589875. The cubic root of 398840400 is about 736.0936101004.

The spelling of 398840400 in words is "three hundred ninety-eight million, eight hundred forty thousand, four hundred".