256717290 has 64 divisors (see below), whose sum is σ = 636056064. Its totient is φ = 66275328.

The previous prime is 256717199. The next prime is 256717291. The reversal of 256717290 is 92717652.

It is not an unprimeable number, because it can be changed into a prime (256717291) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135832 + ... + 137708.

It is an arithmetic number, because the mean of its divisors is an integer number (9938376).

Almost surely, 2^256717290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256717290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (318028032).

256717290 is an abundant number, since it is smaller than the sum of its proper divisors (379338774).

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

256717290 is a wasteful number, since it uses less digits than its factorization.

256717290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2031.

The product of its (nonzero) digits is 52920, while the sum is 39.

The square root of 256717290 is about 16022.3996330138. The cubic root of 256717290 is about 635.5529026143.

The spelling of 256717290 in words is "two hundred fifty-six million, seven hundred seventeen thousand, two hundred ninety".