256421533 has 2 divisors, whose sum is σ = 256421534. Its totient is φ = 256421532.

The previous prime is 256421497. The next prime is 256421573. The reversal of 256421533 is 335124652.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 229764964 + 26656569 = 15158^2 + 5163^2 .

It is a cyclic number.

It is not a de Polignac number, because 256421533 - 2²¹ = 254324381 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 256421495 and 256421504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256421573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128210766 + 128210767.

It is an arithmetic number, because the mean of its divisors is an integer number (128210767).

Almost surely, 2^256421533 is an apocalyptic number.

It is an amenable number.

256421533 is a deficient number, since it is larger than the sum of its proper divisors (1).

256421533 is an equidigital number, since it uses as much as digits as its factorization.

256421533 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21600, while the sum is 31.

The square root of 256421533 is about 16013.1674880393. The cubic root of 256421533 is about 635.3087410949.

The spelling of 256421533 in words is "two hundred fifty-six million, four hundred twenty-one thousand, five hundred thirty-three".