1021000009 has 2 divisors, whose sum is σ = 1021000010. Its totient is φ = 1021000008.

The previous prime is 1021000007. The next prime is 1021000027. The reversal of 1021000009 is 9000001201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1015824384 + 5175625 = 31872^2 + 2275^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021000009 - 2¹ = 1021000007 is a prime.

Together with 1021000007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1021000007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510500004 + 510500005.

It is an arithmetic number, because the mean of its divisors is an integer number (510500005).

Almost surely, 2^1021000009 is an apocalyptic number.

It is an amenable number.

1021000009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021000009 is an equidigital number, since it uses as much as digits as its factorization.

1021000009 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 13.

The square root of 1021000009 is about 31953.0907581724. The cubic root of 1021000009 is about 1006.9515667433.

The spelling of 1021000009 in words is "one billion, twenty-one million, nine", and thus it is an aban number and an uban number.