256910640 has 160 divisors (see below), whose sum is σ = 939749376. Its totient is φ = 56816640.

The previous prime is 256910627. The next prime is 256910651. The reversal of 256910640 is 46019652.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49614 + ... + 54546.

Almost surely, 2^256910640 is an apocalyptic number.

256910640 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 256910640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (469874688).

256910640 is an abundant number, since it is smaller than the sum of its proper divisors (682838736).

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

256910640 is a wasteful number, since it uses less digits than its factorization.

256910640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4987 (or 4981 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 256910640 is about 16028.4322377455. The cubic root of 256910640 is about 635.7124209130.

The spelling of 256910640 in words is "two hundred fifty-six million, nine hundred ten thousand, six hundred forty".