21000122121211 has 4 divisors (see below), whose sum is σ = 21165477413632. Its totient is φ = 20834766828792.

The previous prime is 21000122121191. The next prime is 21000122121227. The reversal of 21000122121211 is 11212122100012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21000122121211 - 2²⁹ = 20999585250299 is a prime.

It is a super-2 number, since 2×21000122121211² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000122181211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82677646020 + ... + 82677646273.

It is an arithmetic number, because the mean of its divisors is an integer number (5291369353408).

Almost surely, 2^{21000122121211} is an apocalyptic number.

21000122121211 is a deficient number, since it is larger than the sum of its proper divisors (165355292421).

21000122121211 is a wasteful number, since it uses less digits than its factorization.

21000122121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165355292420.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21000122121211 its reverse (11212122100012), we get a palindrome (32212244221223).

The spelling of 21000122121211 in words is "twenty-one trillion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred eleven".