1021100009 has 2 divisors, whose sum is σ = 1021100010. Its totient is φ = 1021100008.

The previous prime is 1021099999. The next prime is 1021100011. The reversal of 1021100009 is 9000011201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637057600 + 384042409 = 25240^2 + 19597^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021100009 - 2²⁰ = 1020051433 is a prime.

Together with 1021100011, 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 = 1021099966 and 1021100002.

It is not a weakly prime, because it can be changed into another prime (1021100029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510550004 + 510550005.

It is an arithmetic number, because the mean of its divisors is an integer number (510550005).

Almost surely, 2^1021100009 is an apocalyptic number.

It is an amenable number.

1021100009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021100009 is an equidigital number, since it uses as much as digits as its factorization.

1021100009 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 1021100009 is about 31954.6555137119. The cubic root of 1021100009 is about 1006.9844403537.

The spelling of 1021100009 in words is "one billion, twenty-one million, one hundred thousand, nine".