256528981 has 2 divisors, whose sum is σ = 256528982. Its totient is φ = 256528980.

The previous prime is 256528967. The next prime is 256529003. The reversal of 256528981 is 189825652.

256528981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 243640881 + 12888100 = 15609^2 + 3590^2 .

It is a cyclic number.

It is not a de Polignac number, because 256528981 - 2⁵ = 256528949 is a prime.

It is a super-2 number, since 2×256528981² = 131614236185796722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256528901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128264490 + 128264491.

It is an arithmetic number, because the mean of its divisors is an integer number (128264491).

Almost surely, 2^256528981 is an apocalyptic number.

It is an amenable number.

256528981 is a deficient number, since it is larger than the sum of its proper divisors (1).

256528981 is an equidigital number, since it uses as much as digits as its factorization.

256528981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 46.

The square root of 256528981 is about 16016.5221256052. The cubic root of 256528981 is about 635.3974662504.

The spelling of 256528981 in words is "two hundred fifty-six million, five hundred twenty-eight thousand, nine hundred eighty-one".