1989191 has 4 divisors (see below), whose sum is σ = 1992432. Its totient is φ = 1985952.

The previous prime is 1989161. The next prime is 1989193. The reversal of 1989191 is 1919891.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1989191 - 2¹⁴ = 1972807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 386 + ... + 2031.

It is an arithmetic number, because the mean of its divisors is an integer number (498108).

2^1989191 is an apocalyptic number.

1989191 is a deficient number, since it is larger than the sum of its proper divisors (3241).

1989191 is an equidigital number, since it uses as much as digits as its factorization.

1989191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3240.

The product of its digits is 5832, while the sum is 38.

The square root of 1989191 is about 1410.3868263707. The cubic root of 1989191 is about 125.7647200851.

The spelling of 1989191 in words is "one million, nine hundred eighty-nine thousand, one hundred ninety-one".