256136213520 has 960 divisors, whose sum is σ = 996756703488. Its totient is φ = 58392576000.

The previous prime is 256136213503. The next prime is 256136213527. The reversal of 256136213520 is 25312631652.

256136213520 is a `hidden beast` number, since 2 + 5 + 6 + 1 + 3 + 621 + 3 + 5 + 20 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (256136213527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1327130544 + ... + 1327130736.

Almost surely, 2^256136213520 is an apocalyptic number.

256136213520 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 256136213520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (498378351744).

256136213520 is an abundant number, since it is smaller than the sum of its proper divisors (740620489968).

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

256136213520 is a wasteful number, since it uses less digits than its factorization.

256136213520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The spelling of 256136213520 in words is "two hundred fifty-six billion, one hundred thirty-six million, two hundred thirteen thousand, five hundred twenty".