2215691 has 2 divisors, whose sum is σ = 2215692. Its totient is φ = 2215690.

The previous prime is 2215673. The next prime is 2215693. The reversal of 2215691 is 1965122.

2215691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2215691 - 2¹⁸ = 1953547 is a prime.

Together with 2215693, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2215691.

It is not a weakly prime, because it can be changed into another prime (2215693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1107845 + 1107846.

It is an arithmetic number, because the mean of its divisors is an integer number (1107846).

2^2215691 is an apocalyptic number.

2215691 is a deficient number, since it is larger than the sum of its proper divisors (1).

2215691 is an equidigital number, since it uses as much as digits as its factorization.

2215691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 26.

The square root of 2215691 is about 1488.5197345014. The cubic root of 2215691 is about 130.3676182344.

The spelling of 2215691 in words is "two million, two hundred fifteen thousand, six hundred ninety-one".