2181871 has 2 divisors, whose sum is σ = 2181872. Its totient is φ = 2181870.

The previous prime is 2181869. The next prime is 2181889. The reversal of 2181871 is 1781812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2181871 - 2¹ = 2181869 is a prime.

It is a super-2 number, since 2×2181871² = 9521122121282, which contains 22 as substring.

Together with 2181869, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090935 + 1090936.

It is an arithmetic number, because the mean of its divisors is an integer number (1090936).

2^2181871 is an apocalyptic number.

2181871 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181871 is an equidigital number, since it uses as much as digits as its factorization.

2181871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 896, while the sum is 28.

The square root of 2181871 is about 1477.1157706829. The cubic root of 2181871 is about 129.7009100470.

The spelling of 2181871 in words is "two million, one hundred eighty-one thousand, eight hundred seventy-one".