21221121011 has 4 divisors (see below), whose sum is σ = 21672634272. Its totient is φ = 20769607752.

The previous prime is 21221120989. The next prime is 21221121013. The reversal of 21221121011 is 11012112212.

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 21221121011 - 2¹⁴ = 21221104627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221121013) 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 3 ways as a sum of consecutive naturals, for example, 225756560 + ... + 225756653.

It is an arithmetic number, because the mean of its divisors is an integer number (5418158568).

Almost surely, 2^21221121011 is an apocalyptic number.

21221121011 is a deficient number, since it is larger than the sum of its proper divisors (451513261).

21221121011 is an equidigital number, since it uses as much as digits as its factorization.

21221121011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451513260.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21221121011 its reverse (11012112212), we get a palindrome (32233233223).

The spelling of 21221121011 in words is "twenty-one billion, two hundred twenty-one million, one hundred twenty-one thousand, eleven".