21001022221211 has 32 divisors (see below), whose sum is σ = 21889377543168. Its totient is φ = 20136924138240.

The previous prime is 21001022221159. The next prime is 21001022221271. The reversal of 21001022221211 is 11212222010012.

It is a cyclic number.

It is not a de Polignac number, because 21001022221211 - 2³⁰ = 20999948479387 is a prime.

It is a super-4 number, since 4×21001022221211⁴ (a number of 54 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21001022221211.

It is not an unprimeable number, because it can be changed into a prime (21001022221271) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 185256830 + ... + 185370156.

It is an arithmetic number, because the mean of its divisors is an integer number (684043048224).

Almost surely, 2^{21001022221211} is an apocalyptic number.

21001022221211 is a deficient number, since it is larger than the sum of its proper divisors (888355321957).

21001022221211 is a wasteful number, since it uses less digits than its factorization.

21001022221211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113891.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21001022221211 its reverse (11212222010012), we get a palindrome (32213244231223).

The spelling of 21001022221211 in words is "twenty-one trillion, one billion, twenty-two million, two hundred twenty-one thousand, two hundred eleven".