989210021 has 4 divisors (see below), whose sum is σ = 994928172. Its totient is φ = 983491872.

The previous prime is 989210017. The next prime is 989210051. The reversal of 989210021 is 120012989.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120012989 = 8807 ⋅13627.

It can be written as a sum of positive squares in 2 ways, for example, as 589809796 + 399400225 = 24286^2 + 19985^2 .

It is a cyclic number.

It is not a de Polignac number, because 989210021 - 2² = 989210017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 989210021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989210011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2858816 + ... + 2859161.

It is an arithmetic number, because the mean of its divisors is an integer number (248732043).

Almost surely, 2^989210021 is an apocalyptic number.

It is an amenable number.

989210021 is a deficient number, since it is larger than the sum of its proper divisors (5718151).

989210021 is a wasteful number, since it uses less digits than its factorization.

989210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5718150.

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

The square root of 989210021 is about 31451.7093494137. The cubic root of 989210021 is about 996.3903262666.

The spelling of 989210021 in words is "nine hundred eighty-nine million, two hundred ten thousand, twenty-one".