1891187 has 2 divisors, whose sum is σ = 1891188. Its totient is φ = 1891186.

The previous prime is 1891171. The next prime is 1891189. The reversal of 1891187 is 7811981.

It is a strong prime.

It is an emirp because it is prime and its reverse (7811981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1891187 - 2⁴ = 1891171 is a prime.

Together with 1891189, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1891189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945593 + 945594.

It is an arithmetic number, because the mean of its divisors is an integer number (945594).

2^1891187 is an apocalyptic number.

1891187 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891187 is an equidigital number, since it uses as much as digits as its factorization.

1891187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 35.

The square root of 1891187 is about 1375.2043484515. The cubic root of 1891187 is about 123.6644369937.

The spelling of 1891187 in words is "one million, eight hundred ninety-one thousand, one hundred eighty-seven".