21221001111 has 32 divisors (see below), whose sum is σ = 31293250560. Its totient is φ = 12731088384.

The previous prime is 21221001103. The next prime is 21221001167. The reversal of 21221001111 is 11110012212.

It is not a de Polignac number, because 21221001111 - 2³ = 21221001103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221001101) 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, 82686 + ... + 221988.

It is an arithmetic number, because the mean of its divisors is an integer number (977914080).

Almost surely, 2^21221001111 is an apocalyptic number.

21221001111 is a deficient number, since it is larger than the sum of its proper divisors (10072249449).

21221001111 is a wasteful number, since it uses less digits than its factorization.

21221001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139455.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21221001111 its reverse (11110012212), we get a palindrome (32331013323).

The spelling of 21221001111 in words is "twenty-one billion, two hundred twenty-one million, one thousand, one hundred eleven".