256700640 has 192 divisors, whose sum is σ = 973002240. Its totient is φ = 55572480.

The previous prime is 256700623. The next prime is 256700671. The reversal of 256700640 is 46007652.

256700640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 256700598 and 256700607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 61830 + ... + 65850.

It is an arithmetic number, because the mean of its divisors is an integer number (5067720).

Almost surely, 2^256700640 is an apocalyptic number.

256700640 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 256700640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (486501120).

256700640 is an abundant number, since it is smaller than the sum of its proper divisors (716301600).

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

256700640 is a wasteful number, since it uses less digits than its factorization.

256700640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4065 (or 4057 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 256700640 is about 16021.8800394960. The cubic root of 256700640 is about 635.5391622275.

The spelling of 256700640 in words is "two hundred fifty-six million, seven hundred thousand, six hundred forty".