256621452869 has 2 divisors, whose sum is σ = 256621452870. Its totient is φ = 256621452868.

The previous prime is 256621452851. The next prime is 256621452943. The reversal of 256621452869 is 968254126652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134707350625 + 121914102244 = 367025^2 + 349162^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256621452869 is a prime.

It is a super-4 number, since 4×256621452869⁴ (a number of 47 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256621952869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128310726434 + 128310726435.

It is an arithmetic number, because the mean of its divisors is an integer number (128310726435).

Almost surely, 2^256621452869 is an apocalyptic number.

It is an amenable number.

256621452869 is a deficient number, since it is larger than the sum of its proper divisors (1).

256621452869 is an equidigital number, since it uses as much as digits as its factorization.

256621452869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12441600, while the sum is 56.

The spelling of 256621452869 in words is "two hundred fifty-six billion, six hundred twenty-one million, four hundred fifty-two thousand, eight hundred sixty-nine".