256977649 has 2 divisors, whose sum is σ = 256977650. Its totient is φ = 256977648.

The previous prime is 256977607. The next prime is 256977653. The reversal of 256977649 is 946779652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 133056225 + 123921424 = 11535^2 + 11132^2 .

It is a cyclic number.

It is not a de Polignac number, because 256977649 - 2²³ = 248589041 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256977649.

It is not a weakly prime, because it can be changed into another prime (256917649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128488824 + 128488825.

It is an arithmetic number, because the mean of its divisors is an integer number (128488825).

Almost surely, 2^256977649 is an apocalyptic number.

It is an amenable number.

256977649 is a deficient number, since it is larger than the sum of its proper divisors (1).

256977649 is an equidigital number, since it uses as much as digits as its factorization.

256977649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5715360, while the sum is 55.

The square root of 256977649 is about 16030.5224181871. The cubic root of 256977649 is about 635.7676862387.

The spelling of 256977649 in words is "two hundred fifty-six million, nine hundred seventy-seven thousand, six hundred forty-nine".