21220101212909 has 16 divisors (see below), whose sum is σ = 21568654885680. Its totient is φ = 20874286617600.

The previous prime is 21220101212903. The next prime is 21220101212911. The reversal of 21220101212909 is 90921210102212.

It can be written as a sum of positive squares in 8 ways, for example, as 1103109084100 + 20116992128809 = 1050290^2 + 4485197^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220101212909 - 2¹⁶ = 21220101147373 is a prime.

It is a super-2 number, since 2×21220101212909² (a number of 27 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 (21220101212903) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194494997 + ... + 194604069.

It is an arithmetic number, because the mean of its divisors is an integer number (1348040930355).

Almost surely, 2^{21220101212909} is an apocalyptic number.

It is an amenable number.

21220101212909 is a deficient number, since it is larger than the sum of its proper divisors (348553672771).

21220101212909 is a wasteful number, since it uses less digits than its factorization.

21220101212909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121600.

The product of its (nonzero) digits is 2592, while the sum is 32.

The spelling of 21220101212909 in words is "twenty-one trillion, two hundred twenty billion, one hundred one million, two hundred twelve thousand, nine hundred nine".