200021009 has 2 divisors, whose sum is σ = 200021010. Its totient is φ = 200021008.

The previous prime is 200020991. The next prime is 200021011. The reversal of 200021009 is 900120002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 199798225 + 222784 = 14135^2 + 472^2 .

It is a cyclic number.

It is not a de Polignac number, because 200021009 - 2⁸ = 200020753 is a prime.

Together with 200021011, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 200020984 and 200021002.

It is not a weakly prime, because it can be changed into another prime (200021209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100010504 + 100010505.

It is an arithmetic number, because the mean of its divisors is an integer number (100010505).

Almost surely, 2^200021009 is an apocalyptic number.

It is an amenable number.

200021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

200021009 is an equidigital number, since it uses as much as digits as its factorization.

200021009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 200021009 is about 14142.8783845439. The cubic root of 200021009 is about 584.8240238218.

The spelling of 200021009 in words is "two hundred million, twenty-one thousand, nine".