1256704849 has 4 divisors (see below), whose sum is σ = 1257222964. Its totient is φ = 1256186736.

The previous prime is 1256704819. The next prime is 1256704871. The reversal of 1256704849 is 9484076521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9484076521 = 2137 ⋅4438033.

It can be written as a sum of positive squares in 2 ways, for example, as 1159879249 + 96825600 = 34057^2 + 9840^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256704849 - 2²³ = 1248316241 is a prime.

It is a super-2 number, since 2×1256704849² = 3158614155000225602, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1256704799 and 1256704808.

It is not an unprimeable number, because it can be changed into a prime (1256704819) 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 in 3 ways as a sum of consecutive naturals, for example, 255402 + ... + 260275.

It is an arithmetic number, because the mean of its divisors is an integer number (314305741).

Almost surely, 2^1256704849 is an apocalyptic number.

It is an amenable number.

1256704849 is a deficient number, since it is larger than the sum of its proper divisors (518115).

1256704849 is an equidigital number, since it uses as much as digits as its factorization.

1256704849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518114.

The product of its (nonzero) digits is 483840, while the sum is 46.

The square root of 1256704849 is about 35450.0331311552. The cubic root of 1256704849 is about 1079.1399328298.

The spelling of 1256704849 in words is "one billion, two hundred fifty-six million, seven hundred four thousand, eight hundred forty-nine".