212009989 has 2 divisors, whose sum is σ = 212009990. Its totient is φ = 212009988.

The previous prime is 212009957. The next prime is 212010041. The reversal of 212009989 is 989900212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211469764 + 540225 = 14542^2 + 735^2 .

It is a cyclic number.

It is not a de Polignac number, because 212009989 - 2⁵ = 212009957 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212009939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106004994 + 106004995.

It is an arithmetic number, because the mean of its divisors is an integer number (106004995).

Almost surely, 2^212009989 is an apocalyptic number.

It is an amenable number.

212009989 is a deficient number, since it is larger than the sum of its proper divisors (1).

212009989 is an equidigital number, since it uses as much as digits as its factorization.

212009989 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 212009989 is about 14560.5627981888. The cubic root of 212009989 is about 596.2825606791.

The spelling of 212009989 in words is "two hundred twelve million, nine thousand, nine hundred eighty-nine".