1989917 has 4 divisors (see below), whose sum is σ = 2018016. Its totient is φ = 1961820.

The previous prime is 1989899. The next prime is 1989919. The reversal of 1989917 is 7199891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1989917 - 2¹⁸ = 1727773 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989919) 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 3 ways as a sum of consecutive naturals, for example, 13943 + ... + 14084.

It is an arithmetic number, because the mean of its divisors is an integer number (504504).

2^1989917 is an apocalyptic number.

It is an amenable number.

1989917 is a deficient number, since it is larger than the sum of its proper divisors (28099).

1989917 is an equidigital number, since it uses as much as digits as its factorization.

1989917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28098.

The product of its digits is 40824, while the sum is 44.

The square root of 1989917 is about 1410.6441790898. The cubic root of 1989917 is about 125.7800184453.

The spelling of 1989917 in words is "one million, nine hundred eighty-nine thousand, nine hundred seventeen".