21132212009 has 2 divisors, whose sum is σ = 21132212010. Its totient is φ = 21132212008.

The previous prime is 21132211987. The next prime is 21132212011. The reversal of 21132212009 is 90021223112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18490560400 + 2641651609 = 135980^2 + 51397^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21132212009 is a prime.

Together with 21132212011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21132212039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10566106004 + 10566106005.

It is an arithmetic number, because the mean of its divisors is an integer number (10566106005).

Almost surely, 2^21132212009 is an apocalyptic number.

It is an amenable number.

21132212009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21132212009 is an equidigital number, since it uses as much as digits as its factorization.

21132212009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

It can be divided in two parts, 2113 and 2212009, that added together give a palindrome (2214122).

The spelling of 21132212009 in words is "twenty-one billion, one hundred thirty-two million, two hundred twelve thousand, nine".