1291642641 has 12 divisors (see below), whose sum is σ = 1884179700. Its totient is φ = 852568800.

The previous prime is 1291642637. The next prime is 1291642747. The reversal of 1291642641 is 1462461921.

1291642641 is a `hidden beast` number, since 1 + 2 + 9 + 1 + 6 + 4 + 2 + 641 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 591511041 + 700131600 = 24321^2 + 26460^2 .

It is not a de Polignac number, because 1291642641 - 2² = 1291642637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1291642596 and 1291642605.

It is not an unprimeable number, because it can be changed into a prime (1291642601) 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 11 ways as a sum of consecutive naturals, for example, 709566 + ... + 711383.

It is an arithmetic number, because the mean of its divisors is an integer number (157014975).

Almost surely, 2^1291642641 is an apocalyptic number.

It is an amenable number.

1291642641 is a deficient number, since it is larger than the sum of its proper divisors (592537059).

1291642641 is a wasteful number, since it uses less digits than its factorization.

1291642641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1421056 (or 1421053 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 1291642641 is about 35939.4301707748. The cubic root of 1291642641 is about 1089.0490938058.

The spelling of 1291642641 in words is "one billion, two hundred ninety-one million, six hundred forty-two thousand, six hundred forty-one".