400855644 has 144 divisors (see below), whose sum is σ = 1194298560. Its totient is φ = 111006720.

The previous prime is 400855639. The next prime is 400855681. The reversal of 400855644 is 446558004.

400855644 is a `hidden beast` number, since 4 + 0 + 0 + 8 + 5 + 5 + 644 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 400855599 and 400855608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1367962 + ... + 1368254.

It is an arithmetic number, because the mean of its divisors is an integer number (8293740).

Almost surely, 2^400855644 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 400855644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (597149280).

400855644 is an abundant number, since it is smaller than the sum of its proper divisors (793442916).

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

400855644 is a wasteful number, since it uses less digits than its factorization.

400855644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460 (or 455 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 400855644 is about 20021.3796727398. The cubic root of 400855644 is about 737.3312954726.

The spelling of 400855644 in words is "four hundred million, eight hundred fifty-five thousand, six hundred forty-four".