1891889 has 2 divisors, whose sum is σ = 1891890. Its totient is φ = 1891888.

The previous prime is 1891861. The next prime is 1891907. The reversal of 1891889 is 9881981.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1227664 + 664225 = 1108^2 + 815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1891889 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1891829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945944 + 945945.

It is an arithmetic number, because the mean of its divisors is an integer number (945945).

2^1891889 is an apocalyptic number.

It is an amenable number.

1891889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891889 is an equidigital number, since it uses as much as digits as its factorization.

1891889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 44.

The square root of 1891889 is about 1375.4595595655. The cubic root of 1891889 is about 123.6797363260.

The spelling of 1891889 in words is "one million, eight hundred ninety-one thousand, eight hundred eighty-nine".