21033211221 has 32 divisors (see below), whose sum is σ = 34783626240. Its totient is φ = 12450942000.

The previous prime is 21033211219. The next prime is 21033211237. The reversal of 21033211221 is 12211233012.

21033211221 is a `hidden beast` number, since 210 + 332 + 1 + 122 + 1 = 666.

It is not a de Polignac number, because 21033211221 - 2¹ = 21033211219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21033211194 and 21033211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033211211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 810705 + ... + 836246.

It is an arithmetic number, because the mean of its divisors is an integer number (1086988320).

Almost surely, 2^21033211221 is an apocalyptic number.

It is an amenable number.

21033211221 is a deficient number, since it is larger than the sum of its proper divisors (13750415019).

21033211221 is a wasteful number, since it uses less digits than its factorization.

21033211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647014 (or 1647008 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21033211221 its reverse (12211233012), we get a palindrome (33244444233).

The spelling of 21033211221 in words is "twenty-one billion, thirty-three million, two hundred eleven thousand, two hundred twenty-one".