1291668727 has 2 divisors, whose sum is σ = 1291668728. Its totient is φ = 1291668726.

The previous prime is 1291668629. The next prime is 1291668737. The reversal of 1291668727 is 7278661921.

It is a strong prime.

It is an emirp because it is prime and its reverse (7278661921) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1291668727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291668737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645834363 + 645834364.

It is an arithmetic number, because the mean of its divisors is an integer number (645834364).

Almost surely, 2^1291668727 is an apocalyptic number.

1291668727 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291668727 is an equidigital number, since it uses as much as digits as its factorization.

1291668727 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 49.

The square root of 1291668727 is about 35939.7930851028. The cubic root of 1291668727 is about 1089.0564252308.

The spelling of 1291668727 in words is "one billion, two hundred ninety-one million, six hundred sixty-eight thousand, seven hundred twenty-seven".