1261481849 has 4 divisors (see below), whose sum is σ = 1264395636. Its totient is φ = 1258568064.

The previous prime is 1261481831. The next prime is 1261481863. The reversal of 1261481849 is 9481841621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9481841621 = 7 ⋅1354548803.

It can be written as a sum of positive squares in 2 ways, for example, as 658435600 + 603046249 = 25660^2 + 24557^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261481849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261981849) 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, 1456244 + ... + 1457109.

It is an arithmetic number, because the mean of its divisors is an integer number (316098909).

Almost surely, 2^1261481849 is an apocalyptic number.

It is an amenable number.

1261481849 is a deficient number, since it is larger than the sum of its proper divisors (2913787).

1261481849 is an equidigital number, since it uses as much as digits as its factorization.

1261481849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2913786.

The product of its digits is 110592, while the sum is 44.

The square root of 1261481849 is about 35517.3457482397. The cubic root of 1261481849 is about 1080.5055500654.

The spelling of 1261481849 in words is "one billion, two hundred sixty-one million, four hundred eighty-one thousand, eight hundred forty-nine".