1285857257 has 2 divisors, whose sum is σ = 1285857258. Its totient is φ = 1285857256.

The previous prime is 1285857217. The next prime is 1285857283. The reversal of 1285857257 is 7527585821.

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., 910892761 + 374964496 = 30181^2 + 19364^2 .

It is a cyclic number.

It is not a de Polignac number, because 1285857257 - 2⁶ = 1285857193 is a prime.

It is not a weakly prime, because it can be changed into another prime (1285857217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 642928628 + 642928629.

It is an arithmetic number, because the mean of its divisors is an integer number (642928629).

Almost surely, 2^1285857257 is an apocalyptic number.

It is an amenable number.

1285857257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1285857257 is an equidigital number, since it uses as much as digits as its factorization.

1285857257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1568000, while the sum is 50.

The square root of 1285857257 is about 35858.8518639401. The cubic root of 1285857257 is about 1087.4206770345.

The spelling of 1285857257 in words is "one billion, two hundred eighty-five million, eight hundred fifty-seven thousand, two hundred fifty-seven".