256512906 has 60 divisors (see below), whose sum is σ = 620771382. Its totient is φ = 78700896.

The previous prime is 256512889. The next prime is 256512923. The reversal of 256512906 is 609215652.

256512906 is a `hidden beast` number, since 2 + 56 + 512 + 90 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (256512889) and next prime (256512923).

It can be written as a sum of positive squares in 3 ways, for example, as 227255625 + 29257281 = 15075^2 + 5409^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 734820 + ... + 735168.

Almost surely, 2^256512906 is an apocalyptic number.

256512906 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 256512906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310385691).

256512906 is an abundant number, since it is smaller than the sum of its proper divisors (364258476).

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

256512906 is an equidigital number, since it uses as much as digits as its factorization.

256512906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725 (or 367 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 256512906 is about 16016.0202921949. The cubic root of 256512906 is about 635.3841938999.

The spelling of 256512906 in words is "two hundred fifty-six million, five hundred twelve thousand, nine hundred six".