400409856 has 432 divisors, whose sum is σ = 1502487168. Its totient is φ = 99532800.

The previous prime is 400409839. The next prime is 400409869. The reversal of 400409856 is 658904004.

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

It is a self number, because there is not a number n which added to its sum of digits gives 400409856.

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, 6564066 + ... + 6564126.

Almost surely, 2^400409856 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 400409856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (751243584).

400409856 is an abundant number, since it is smaller than the sum of its proper divisors (1102077312).

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

400409856 is a wasteful number, since it uses less digits than its factorization.

400409856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 400409856 is about 20010.2437766260. The cubic root of 400409856 is about 737.0578675611.

The spelling of 400409856 in words is "four hundred million, four hundred nine thousand, eight hundred fifty-six".