21120989 has 8 divisors (see below), whose sum is σ = 22410240. Its totient is φ = 19849536.

The previous prime is 21120959. The next prime is 21121003. The reversal of 21120989 is 98902112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21120989 - 2⁸ = 21120733 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 (21120929) 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 7 ways as a sum of consecutive naturals, for example, 1964 + ... + 6789.

It is an arithmetic number, because the mean of its divisors is an integer number (2801280).

Almost surely, 2^21120989 is an apocalyptic number.

It is an amenable number.

21120989 is a deficient number, since it is larger than the sum of its proper divisors (1289251).

21120989 is a wasteful number, since it uses less digits than its factorization.

21120989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8899.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 21120989 is about 4595.7577177219. The cubic root of 21120989 is about 276.4212437850.

The spelling of 21120989 in words is "twenty-one million, one hundred twenty thousand, nine hundred eighty-nine".