9891989 has 4 divisors (see below), whose sum is σ = 10412640. Its totient is φ = 9371340.

The previous prime is 9891953. The next prime is 9891991.

9891989 is nontrivially palindromic in base 10.

9891989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 9891989 - 2⁸ = 9891733 is a prime.

It is a super-2 number, since 2×9891989² = 195702892752242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9891989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9891289) 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, 260297 + ... + 260334.

It is an arithmetic number, because the mean of its divisors is an integer number (2603160).

Almost surely, 2^9891989 is an apocalyptic number.

It is an amenable number.

9891989 is a deficient number, since it is larger than the sum of its proper divisors (520651).

9891989 is a wasteful number, since it uses less digits than its factorization.

9891989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520650.

The product of its digits is 419904, while the sum is 53.

The square root of 9891989 is about 3145.1532554074. The cubic root of 9891989 is about 214.6649839230.

The spelling of 9891989 in words is "nine million, eight hundred ninety-one thousand, nine hundred eighty-nine".