21202112309 has 32 divisors (see below), whose sum is σ = 26839641600. Its totient is φ = 16328632320.

The previous prime is 21202112303. The next prime is 21202112311. The reversal of 21202112309 is 90321120212.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21202112309 is a prime.

It is a super-2 number, since 2×21202112309² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202112303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 272624 + ... + 341654.

It is an arithmetic number, because the mean of its divisors is an integer number (838738800).

Almost surely, 2^21202112309 is an apocalyptic number.

21202112309 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21202112309 is a deficient number, since it is larger than the sum of its proper divisors (5637529291).

21202112309 is a wasteful number, since it uses less digits than its factorization.

21202112309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69173.

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

The spelling of 21202112309 in words is "twenty-one billion, two hundred two million, one hundred twelve thousand, three hundred nine".