400421504 has 128 divisors (see below), whose sum is σ = 983769600. Its totient is φ = 158505984.

The previous prime is 400421501. The next prime is 400421509. The reversal of 400421504 is 405124004.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400421501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 731759 + ... + 732305.

It is an arithmetic number, because the mean of its divisors is an integer number (7685700).

Almost surely, 2^400421504 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 400421504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (491884800).

400421504 is an abundant number, since it is smaller than the sum of its proper divisors (583348096).

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

400421504 is a wasteful number, since it uses less digits than its factorization.

400421504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630 (or 618 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 400421504 is about 20010.5348254363. The cubic root of 400421504 is about 737.0650145437.

Adding to 400421504 its reverse (405124004), we get a palindrome (805545508).

The spelling of 400421504 in words is "four hundred million, four hundred twenty-one thousand, five hundred four".