400021888 has 192 divisors, whose sum is σ = 1004659200. Its totient is φ = 157774848.

The previous prime is 400021859. The next prime is 400021891. The reversal of 400021888 is 888120004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6780003 + ... + 6780061.

It is an arithmetic number, because the mean of its divisors is an integer number (5232600).

Almost surely, 2^400021888 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 400021888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (502329600).

400021888 is an abundant number, since it is smaller than the sum of its proper divisors (604637312).

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

400021888 is a wasteful number, since it uses less digits than its factorization.

400021888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 400021888 is about 20000.5471925145. The cubic root of 400021888 is about 736.8197388299.

The spelling of 400021888 in words is "four hundred million, twenty-one thousand, eight hundred eighty-eight".