256804688761 has 2 divisors, whose sum is σ = 256804688762. Its totient is φ = 256804688760.

The previous prime is 256804688747. The next prime is 256804688809. The reversal of 256804688761 is 167886408652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 196954002025 + 59850686736 = 443795^2 + 244644^2 .

It is a cyclic number.

It is not a de Polignac number, because 256804688761 - 2¹³ = 256804680569 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256804688761.

It is not a weakly prime, because it can be changed into another prime (256804683761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128402344380 + 128402344381.

It is an arithmetic number, because the mean of its divisors is an integer number (128402344381).

Almost surely, 2^256804688761 is an apocalyptic number.

It is an amenable number.

256804688761 is a deficient number, since it is larger than the sum of its proper divisors (1).

256804688761 is an equidigital number, since it uses as much as digits as its factorization.

256804688761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30965760, while the sum is 61.

The spelling of 256804688761 in words is "two hundred fifty-six billion, eight hundred four million, six hundred eighty-eight thousand, seven hundred sixty-one".