21221354306611 has 4 divisors (see below), whose sum is σ = 21953125144800. Its totient is φ = 20489583468424.

The previous prime is 21221354306599. The next prime is 21221354306617. The reversal of 21221354306611 is 11660345312212.

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 21221354306611 - 2⁷ = 21221354306483 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221354306617) 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, 365885419051 + ... + 365885419108.

It is an arithmetic number, because the mean of its divisors is an integer number (5488281286200).

Almost surely, 2^{21221354306611} is an apocalyptic number.

21221354306611 is a deficient number, since it is larger than the sum of its proper divisors (731770838189).

21221354306611 is an equidigital number, since it uses as much as digits as its factorization.

21221354306611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731770838188.

The product of its (nonzero) digits is 51840, while the sum is 37.

Adding to 21221354306611 its reverse (11660345312212), we get a palindrome (32881699618823).

The spelling of 21221354306611 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred fifty-four million, three hundred six thousand, six hundred eleven".