256856216400 has 1800 divisors, whose sum is σ = 1175863239936. Its totient is φ = 53299814400.

The previous prime is 256856216377. The next prime is 256856216401. The reversal of 256856216400 is 4612658652.

256856216400 is a `hidden beast` number, since 2 + 568 + 5 + 6 + 21 + 64 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1800).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256856216401) by changing a digit.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 836665047 + ... + 836665353.

Almost surely, 2^256856216400 is an apocalyptic number.

256856216400 is a gapful number since it is divisible by the number (20) 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 256856216400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (587931619968).

256856216400 is an abundant number, since it is smaller than the sum of its proper divisors (919007023536).

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

256856216400 is a wasteful number, since it uses less digits than its factorization.

256856216400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399 (or 372 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 45.

The spelling of 256856216400 in words is "two hundred fifty-six billion, eight hundred fifty-six million, two hundred sixteen thousand, four hundred".