400321440 has 480 divisors, whose sum is σ = 1580705280. Its totient is φ = 94887936.

The previous prime is 400321421. The next prime is 400321487. The reversal of 400321440 is 44123004.

It is a tau number, because it is divible by the number of its divisors (480).

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5067321 + ... + 5067399.

It is an arithmetic number, because the mean of its divisors is an integer number (3293136).

Almost surely, 2^400321440 is an apocalyptic number.

400321440 is a gapful number since it is divisible by the number (40) 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 400321440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (790352640).

400321440 is an abundant number, since it is smaller than the sum of its proper divisors (1180383840).

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

400321440 is a wasteful number, since it uses less digits than its factorization.

400321440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 129 counting only the distinct ones).

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

The square root of 400321440 is about 20008.0343862160. The cubic root of 400321440 is about 737.0036127314.

Adding to 400321440 its reverse (44123004), we get a palindrome (444444444).

The spelling of 400321440 in words is "four hundred million, three hundred twenty-one thousand, four hundred forty".