1891989 has 24 divisors (see below), whose sum is σ = 3088800. Its totient is φ = 1105440.

The previous prime is 1891987. The next prime is 1891991. The reversal of 1891989 is 9891981.

It is an interprime number because it is at equal distance from previous prime (1891987) and next prime (1891991).

It is not a de Polignac number, because 1891989 - 2¹ = 1891987 is a prime.

It is a super-2 number, since 2×1891989² = 7159244752242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1891987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2542 + ... + 3200.

It is an arithmetic number, because the mean of its divisors is an integer number (128700).

2^1891989 is an apocalyptic number.

It is an amenable number.

1891989 is a deficient number, since it is larger than the sum of its proper divisors (1196811).

1891989 is a wasteful number, since it uses less digits than its factorization.

1891989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 705 (or 702 counting only the distinct ones).

The product of its digits is 46656, while the sum is 45.

The square root of 1891989 is about 1375.4959105719. The cubic root of 1891989 is about 123.6819154101.

The spelling of 1891989 in words is "one million, eight hundred ninety-one thousand, nine hundred eighty-nine".