1291647281 has 8 divisors (see below), whose sum is σ = 1295284584. Its totient is φ = 1288016640.

The previous prime is 1291647257. The next prime is 1291647283. The reversal of 1291647281 is 1827461921.

It can be written as a sum of positive squares in 4 ways, for example, as 150896656 + 1140750625 = 12284^2 + 33775^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1291647281 - 2²⁶ = 1224538417 is a prime.

It is a super-2 number, since 2×1291647281² = 3336705397029385922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1291647283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 995225 + ... + 996521.

It is an arithmetic number, because the mean of its divisors is an integer number (161910573).

Almost surely, 2^1291647281 is an apocalyptic number.

It is an amenable number.

1291647281 is a deficient number, since it is larger than the sum of its proper divisors (3637303).

1291647281 is a wasteful number, since it uses less digits than its factorization.

1291647281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3331.

The product of its digits is 48384, while the sum is 41.

The square root of 1291647281 is about 35939.4947237715. The cubic root of 1291647281 is about 1089.0503978769.

The spelling of 1291647281 in words is "one billion, two hundred ninety-one million, six hundred forty-seven thousand, two hundred eighty-one".