256136621400 has 288 divisors, whose sum is σ = 947169288000. Its totient is φ = 61512902400.

The previous prime is 256136621399. The next prime is 256136621417. The reversal of 256136621400 is 4126631652.

256136621400 is a `hidden beast` number, since 2 + 561 + 36 + 6 + 21 + 40 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2058151 + ... + 2179049.

It is an arithmetic number, because the mean of its divisors is an integer number (3288782250).

Almost surely, 2^256136621400 is an apocalyptic number.

256136621400 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 256136621400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (473584644000).

256136621400 is an abundant number, since it is smaller than the sum of its proper divisors (691032666600).

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

256136621400 is a wasteful number, since it uses less digits than its factorization.

256136621400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121039 (or 121027 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

It can be divided in two parts, 2561 and 36621400, that added together give a triangular number (36623961 = T₈₅₅₈).

The spelling of 256136621400 in words is "two hundred fifty-six billion, one hundred thirty-six million, six hundred twenty-one thousand, four hundred".