256401252540 has 288 divisors, whose sum is σ = 831205380096. Its totient is φ = 63752140800.

The previous prime is 256401252517. The next prime is 256401252559. The reversal of 256401252540 is 45252104652.

256401252540 is a `hidden beast` number, since 2 + 5 + 64 + 0 + 1 + 2 + 52 + 540 = 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 = 256401252495 and 256401252504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 297104149 + ... + 297105011.

It is an arithmetic number, because the mean of its divisors is an integer number (2886129792).

Almost surely, 2^256401252540 is an apocalyptic number.

256401252540 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 256401252540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (415602690048).

256401252540 is an abundant number, since it is smaller than the sum of its proper divisors (574804127556).

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

256401252540 is a wasteful number, since it uses less digits than its factorization.

256401252540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1689 (or 1684 counting only the distinct ones).

The product of its (nonzero) digits is 96000, while the sum is 36.

The spelling of 256401252540 in words is "two hundred fifty-six billion, four hundred one million, two hundred fifty-two thousand, five hundred forty".