256863357473 has 2 divisors, whose sum is σ = 256863357474. Its totient is φ = 256863357472.

The previous prime is 256863357461. The next prime is 256863357481. The reversal of 256863357473 is 374753368652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 255295751824 + 1567605649 = 505268^2 + 39593^2 .

It is a cyclic number.

It is not a de Polignac number, because 256863357473 - 2⁶ = 256863357409 is a prime.

It is not a weakly prime, because it can be changed into another prime (256863351473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128431678736 + 128431678737.

It is an arithmetic number, because the mean of its divisors is an integer number (128431678737).

Almost surely, 2^256863357473 is an apocalyptic number.

It is an amenable number.

256863357473 is a deficient number, since it is larger than the sum of its proper divisors (1).

256863357473 is an equidigital number, since it uses as much as digits as its factorization.

256863357473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 76204800, while the sum is 59.

The spelling of 256863357473 in words is "two hundred fifty-six billion, eight hundred sixty-three million, three hundred fifty-seven thousand, four hundred seventy-three".