2021012009 has 2 divisors, whose sum is σ = 2021012010. Its totient is φ = 2021012008.

The previous prime is 2021011981. The next prime is 2021012033. The reversal of 2021012009 is 9002101202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1989427609 + 31584400 = 44603^2 + 5620^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021012009 - 2²⁰ = 2019963433 is a prime.

It is not a weakly prime, because it can be changed into another prime (2021012809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010506004 + 1010506005.

It is an arithmetic number, because the mean of its divisors is an integer number (1010506005).

Almost surely, 2^2021012009 is an apocalyptic number.

It is an amenable number.

2021012009 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021012009 is an equidigital number, since it uses as much as digits as its factorization.

2021012009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 2021012009 is about 44955.6671510945. The cubic root of 2021012009 is about 1264.3179331710.

The spelling of 2021012009 in words is "two billion, twenty-one million, twelve thousand, nine".