256403340 has 192 divisors, whose sum is σ = 841921920. Its totient is φ = 64696320.

The previous prime is 256403317. The next prime is 256403363. The reversal of 256403340 is 43304652.

256403340 is a `hidden beast` number, since 256 + 403 + 3 + 4 + 0 = 666.

256403340 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (256403317) and next prime (256403363).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 819024 + ... + 819336.

It is an arithmetic number, because the mean of its divisors is an integer number (4385010).

Almost surely, 2^256403340 is an apocalyptic number.

256403340 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 256403340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (420960960).

256403340 is an abundant number, since it is smaller than the sum of its proper divisors (585518580).

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

256403340 is a wasteful number, since it uses less digits than its factorization.

256403340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 27.

The square root of 256403340 is about 16012.5994142113. The cubic root of 256403340 is about 635.2937157768.

Adding to 256403340 its reverse (43304652), we get a palindrome (299707992).

The spelling of 256403340 in words is "two hundred fifty-six million, four hundred three thousand, three hundred forty".