21102010009 has 2 divisors, whose sum is σ = 21102010010. Its totient is φ = 21102010008.

The previous prime is 21102009989. The next prime is 21102010043. The reversal of 21102010009 is 90001020112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13637568400 + 7464441609 = 116780^2 + 86397^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102010009 - 2²⁷ = 20967792281 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21102009974 and 21102010001.

It is not a weakly prime, because it can be changed into another prime (21102010079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551005004 + 10551005005.

It is an arithmetic number, because the mean of its divisors is an integer number (10551005005).

Almost surely, 2^21102010009 is an apocalyptic number.

It is an amenable number.

21102010009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102010009 is an equidigital number, since it uses as much as digits as its factorization.

21102010009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 16.

The spelling of 21102010009 in words is "twenty-one billion, one hundred two million, ten thousand, nine".