256777771 has 2 divisors, whose sum is σ = 256777772. Its totient is φ = 256777770.

The previous prime is 256777757. The next prime is 256777777. The reversal of 256777771 is 177777652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256777771 - 2⁹ = 256777259 is a prime.

It is not a weakly prime, because it can be changed into another prime (256777777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128388885 + 128388886.

It is an arithmetic number, because the mean of its divisors is an integer number (128388886).

Almost surely, 2^256777771 is an apocalyptic number.

256777771 is a deficient number, since it is larger than the sum of its proper divisors (1).

256777771 is an equidigital number, since it uses as much as digits as its factorization.

256777771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008420, while the sum is 49.

The square root of 256777771 is about 16024.2869108114. The cubic root of 256777771 is about 635.6028094682.

The spelling of 256777771 in words is "two hundred fifty-six million, seven hundred seventy-seven thousand, seven hundred seventy-one".