256354624781 has 2 divisors, whose sum is σ = 256354624782. Its totient is φ = 256354624780.

The previous prime is 256354624769. The next prime is 256354624783. The reversal of 256354624781 is 187426453652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 251853422500 + 4501202281 = 501850^2 + 67091^2 .

It is a cyclic number.

It is not a de Polignac number, because 256354624781 - 2¹⁸ = 256354362637 is a prime.

It is a super-2 number, since 2×256354624781² (a number of 24 digits) contains 22 as substring.

Together with 256354624783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256354624783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128177312390 + 128177312391.

It is an arithmetic number, because the mean of its divisors is an integer number (128177312391).

Almost surely, 2^256354624781 is an apocalyptic number.

It is an amenable number.

256354624781 is a deficient number, since it is larger than the sum of its proper divisors (1).

256354624781 is an equidigital number, since it uses as much as digits as its factorization.

256354624781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9676800, while the sum is 53.

The spelling of 256354624781 in words is "two hundred fifty-six billion, three hundred fifty-four million, six hundred twenty-four thousand, seven hundred eighty-one".