2091691687 has 2 divisors, whose sum is σ = 2091691688. Its totient is φ = 2091691686.

The previous prime is 2091691669. The next prime is 2091691709. The reversal of 2091691687 is 7861961902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2091691687 is a prime.

It is a super-2 number, since 2×2091691687² = 8750348226929811938, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2091691687.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2091691387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1045845843 + 1045845844.

It is an arithmetic number, because the mean of its divisors is an integer number (1045845844).

Almost surely, 2^2091691687 is an apocalyptic number.

2091691687 is a deficient number, since it is larger than the sum of its proper divisors (1).

2091691687 is an equidigital number, since it uses as much as digits as its factorization.

2091691687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 326592, while the sum is 49.

The square root of 2091691687 is about 45735.0159833797. The cubic root of 2091691687 is about 1278.8881309334. Note that the first 3 decimals are identical.

The spelling of 2091691687 in words is "two billion, ninety-one million, six hundred ninety-one thousand, six hundred eighty-seven".