400320144 has 140 divisors (see below), whose sum is σ = 1329297856. Its totient is φ = 114353856.

The previous prime is 400320113. The next prime is 400320157. The reversal of 400320144 is 441023004.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 79197 + ... + 84099.

Almost surely, 2^400320144 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400320144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (664648928).

400320144 is an abundant number, since it is smaller than the sum of its proper divisors (928977712).

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

400320144 is an equidigital number, since it uses as much as digits as its factorization.

400320144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4936 (or 4915 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 400320144 is about 20008.0019992002. The cubic root of 400320144 is about 737.0028174058.

Adding to 400320144 its reverse (441023004), we get a palindrome (841343148).

The spelling of 400320144 in words is "four hundred million, three hundred twenty thousand, one hundred forty-four".