1256481209 has 2 divisors, whose sum is σ = 1256481210. Its totient is φ = 1256481208.

The previous prime is 1256481197. The next prime is 1256481223. The reversal of 1256481209 is 9021846521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1191630400 + 64850809 = 34520^2 + 8053^2 .

It is an emirp because it is prime and its reverse (9021846521) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256481209 is a prime.

It is not a weakly prime, because it can be changed into another prime (1256481269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628240604 + 628240605.

It is an arithmetic number, because the mean of its divisors is an integer number (628240605).

Almost surely, 2^1256481209 is an apocalyptic number.

It is an amenable number.

1256481209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256481209 is an equidigital number, since it uses as much as digits as its factorization.

1256481209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 1256481209 is about 35446.8786919243. The cubic root of 1256481209 is about 1079.0759153658.

The spelling of 1256481209 in words is "one billion, two hundred fifty-six million, four hundred eighty-one thousand, two hundred nine".