2165591 has 2 divisors, whose sum is σ = 2165592. Its totient is φ = 2165590.

The previous prime is 2165557. The next prime is 2165593. The reversal of 2165591 is 1955612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2165591 - 2¹⁴ = 2149207 is a prime.

Together with 2165593, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2165593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1082795 + 1082796.

It is an arithmetic number, because the mean of its divisors is an integer number (1082796).

2^2165591 is an apocalyptic number.

2165591 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165591 is an equidigital number, since it uses as much as digits as its factorization.

2165591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2700, while the sum is 29.

The square root of 2165591 is about 1471.5947132278. The cubic root of 2165591 is about 129.3775172015.

The spelling of 2165591 in words is "two million, one hundred sixty-five thousand, five hundred ninety-one".