2021009 has 2 divisors, whose sum is σ = 2021010. Its totient is φ = 2021008.

The previous prime is 2021003. The next prime is 2021017. The reversal of 2021009 is 9001202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1960000 + 61009 = 1400^2 + 247^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2021009 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 2020984 and 2021002.

It is not a weakly prime, because it can be changed into another prime (2021003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010504 + 1010505.

It is an arithmetic number, because the mean of its divisors is an integer number (1010505).

2^2021009 is an apocalyptic number.

It is an amenable number.

2021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021009 is an equidigital number, since it uses as much as digits as its factorization.

2021009 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 2021009 is about 1421.6219610009. The cubic root of 2021009 is about 126.4317305707.

The spelling of 2021009 in words is "two million, twenty-one thousand, nine".