211001009 has 2 divisors, whose sum is σ = 211001010.
Its totient is φ = 211001008.
The previous prime is 211000981. The next prime is 211001033. The reversal of 211001009 is 900100112.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 116035984 + 94965025 = 10772^2 + 9745^2
It is a cyclic number.
It is not a de Polignac number, because 211001009 - 220 = 209952433 is a prime.
It is a Sophie Germain prime.
It is a Curzon number.
It is a junction number, because it is equal to n+sod(n) for n = 211000984 and 211001002.
It is not a weakly prime, because it can be changed into another prime (211001309) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105500504 + 105500505.
It is an arithmetic number, because the mean of its divisors is an integer number (105500505).
Almost surely, 2211001009 is an apocalyptic number.
It is an amenable number.
211001009 is a deficient number, since it is larger than the sum of its proper divisors (1).
211001009 is an equidigital number, since it uses as much as digits as its factorization.
211001009 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 18, while the sum is 14.
The square root of 211001009 is about 14525.8737775047.
The cubic root of 211001009 is about 595.3351302732.
The spelling of 211001009 in words is "two hundred eleven million, one thousand, nine".