256049640 has 256 divisors, whose sum is σ = 1064448000. Its totient is φ = 53187840.

The previous prime is 256049581. The next prime is 256049641. The reversal of 256049640 is 46940652.

256049640 is a `hidden beast` number, since 2 + 5 + 6 + 0 + 4 + 9 + 640 = 666.

It is a super-2 number, since 2×256049640² = 131122836288259200, which contains 22 as substring.

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 = 256049595 and 256049604.

It is not an unprimeable number, because it can be changed into a prime (256049641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 81621 + ... + 84699.

It is an arithmetic number, because the mean of its divisors is an integer number (4158000).

Almost surely, 2^256049640 is an apocalyptic number.

256049640 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 256049640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (532224000).

256049640 is an abundant number, since it is smaller than the sum of its proper divisors (808398360).

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

256049640 is a wasteful number, since it uses less digits than its factorization.

256049640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3117 (or 3107 counting only the distinct ones).

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

The square root of 256049640 is about 16001.5511748080. The cubic root of 256049640 is about 635.0014590662.

The spelling of 256049640 in words is "two hundred fifty-six million, forty-nine thousand, six hundred forty".