2188691 has 2 divisors, whose sum is σ = 2188692. Its totient is φ = 2188690.

The previous prime is 2188687. The next prime is 2188729. The reversal of 2188691 is 1968812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2188691 - 2² = 2188687 is a prime.

It is not a weakly prime, because it can be changed into another prime (2188651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1094345 + 1094346.

It is an arithmetic number, because the mean of its divisors is an integer number (1094346).

2^2188691 is an apocalyptic number.

2188691 is a deficient number, since it is larger than the sum of its proper divisors (1).

2188691 is an equidigital number, since it uses as much as digits as its factorization.

2188691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 35.

The square root of 2188691 is about 1479.4225224729. The cubic root of 2188691 is about 129.8359073595.

The spelling of 2188691 in words is "two million, one hundred eighty-eight thousand, six hundred ninety-one".