256722081 has 16 divisors (see below), whose sum is σ = 426759168. Its totient is φ = 133362000.

The previous prime is 256722079. The next prime is 256722097. The reversal of 256722081 is 180227652.

It is not a de Polignac number, because 256722081 - 2¹ = 256722079 is a prime.

It is a super-2 number, since 2×256722081² = 131812453745941122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (256722001) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 555445 + ... + 555906.

It is an arithmetic number, because the mean of its divisors is an integer number (26672448).

Almost surely, 2^256722081 is an apocalyptic number.

256722081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

256722081 is a deficient number, since it is larger than the sum of its proper divisors (170037087).

256722081 is a wasteful number, since it uses less digits than its factorization.

256722081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111372.

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 256722081 is about 16022.5491417564. The cubic root of 256722081 is about 635.5568562696.

The spelling of 256722081 in words is "two hundred fifty-six million, seven hundred twenty-two thousand, eighty-one".