21212000109 has 12 divisors (see below), whose sum is σ = 30721704156. Its totient is φ = 14103418752.

The previous prime is 21212000107. The next prime is 21212000119. The reversal of 21212000109 is 90100021212.

It can be written as a sum of positive squares in 2 ways, for example, as 8099460009 + 13112540100 = 89997^2 + 114510^2 .

It is not a de Polignac number, because 21212000109 - 2¹ = 21212000107 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212000091 and 21212000100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212000107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3156012 + ... + 3162725.

It is an arithmetic number, because the mean of its divisors is an integer number (2560142013).

Almost surely, 2^21212000109 is an apocalyptic number.

It is an amenable number.

21212000109 is a deficient number, since it is larger than the sum of its proper divisors (9509704047).

21212000109 is a wasteful number, since it uses less digits than its factorization.

21212000109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6319116 (or 6319113 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The spelling of 21212000109 in words is "twenty-one billion, two hundred twelve million, one hundred nine", and thus it is an aban number.