20211989 has 8 divisors (see below), whose sum is σ = 23359680. Its totient is φ = 17129376.

The previous prime is 20211977. The next prime is 20212001. The reversal of 20211989 is 98911202.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20211977) and next prime (20212001).

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 20211989 - 2⁴ = 20211973 is a prime.

It is a super-2 number, since 2×20211989² = 817048998672242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15599 + ... + 16844.

It is an arithmetic number, because the mean of its divisors is an integer number (2919960).

Almost surely, 2^20211989 is an apocalyptic number.

It is an amenable number.

20211989 is a deficient number, since it is larger than the sum of its proper divisors (3147691).

20211989 is an equidigital number, since it uses as much as digits as its factorization.

20211989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32539.

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

The square root of 20211989 is about 4495.7745717507. The cubic root of 20211989 is about 272.3974374850.

The spelling of 20211989 in words is "twenty million, two hundred eleven thousand, nine hundred eighty-nine".