21002211111 has 32 divisors (see below), whose sum is σ = 34979033088. Its totient is φ = 10930936320.

The previous prime is 21002211073. The next prime is 21002211119. The reversal of 21002211111 is 11111220012.

It is not a de Polignac number, because 21002211111 - 2¹⁵ = 21002178343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002211119) 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, 937800 + ... + 959933.

It is an arithmetic number, because the mean of its divisors is an integer number (1093094784).

Almost surely, 2^21002211111 is an apocalyptic number.

21002211111 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21002211111 is a deficient number, since it is larger than the sum of its proper divisors (13976821977).

21002211111 is a wasteful number, since it uses less digits than its factorization.

21002211111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1897791.

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

Adding to 21002211111 its reverse (11111220012), we get a palindrome (32113431123).

The spelling of 21002211111 in words is "twenty-one billion, two million, two hundred eleven thousand, one hundred eleven".