2021009989 has 2 divisors, whose sum is σ = 2021009990. Its totient is φ = 2021009988.

The previous prime is 2021009987. The next prime is 2021009999. The reversal of 2021009989 is 9899001202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1895905764 + 125104225 = 43542^2 + 11185^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021009989 - 2¹ = 2021009987 is a prime.

Together with 2021009987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2021009983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010504994 + 1010504995.

It is an arithmetic number, because the mean of its divisors is an integer number (1010504995).

Almost surely, 2^2021009989 is an apocalyptic number.

It is an amenable number.

2021009989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021009989 is an equidigital number, since it uses as much as digits as its factorization.

2021009989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 2021009989 is about 44955.6446845110. The cubic root of 2021009989 is about 1264.3175119426.

The spelling of 2021009989 in words is "two billion, twenty-one million, nine thousand, nine hundred eighty-nine".