2149991 has 2 divisors, whose sum is σ = 2149992. Its totient is φ = 2149990.

The previous prime is 2149937. The next prime is 2149993. The reversal of 2149991 is 1999412.

2149991 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 a de Polignac number, because none of the positive numbers 2^k-2149991 is a prime.

It is a super-2 number, since 2×2149991² = 9244922600162, which contains 22 as substring.

Together with 2149993, 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 (2149993) 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, 1074995 + 1074996.

It is an arithmetic number, because the mean of its divisors is an integer number (1074996).

2^2149991 is an apocalyptic number.

2149991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2149991 is an equidigital number, since it uses as much as digits as its factorization.

2149991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 35.

The square root of 2149991 is about 1466.2847608838. The cubic root of 2149991 is about 129.0661079747.

The spelling of 2149991 in words is "two million, one hundred forty-nine thousand, nine hundred ninety-one".