256777777 has 2 divisors, whose sum is σ = 256777778. Its totient is φ = 256777776.

The previous prime is 256777771. The next prime is 256777783. The reversal of 256777777 is 777777652.

It is a balanced prime because it is at equal distance from previous prime (256777771) and next prime (256777783).

It can be written as a sum of positive squares in only one way, i.e., 232532001 + 24245776 = 15249^2 + 4924^2 .

It is a cyclic number.

It is not a de Polignac number, because 256777777 - 2¹⁹ = 256253489 is a prime.

It is a super-2 number, since 2×256777777² = 131869653522123458, which contains 22 as substring.

It is a plaindrome in base 10.

It is not a weakly prime, because it can be changed into another prime (256777771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128388888 + 128388889.

It is an arithmetic number, because the mean of its divisors is an integer number (128388889).

Almost surely, 2^256777777 is an apocalyptic number.

It is an amenable number.

256777777 is a deficient number, since it is larger than the sum of its proper divisors (1).

256777777 is an equidigital number, since it uses as much as digits as its factorization.

256777777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7058940, while the sum is 55.

The square root of 256777777 is about 16024.2870980272. The cubic root of 256777777 is about 635.6028144188.

The spelling of 256777777 in words is "two hundred fifty-six million, seven hundred seventy-seven thousand, seven hundred seventy-seven".