21210311111 has 32 divisors (see below), whose sum is σ = 23901067008. Its totient is φ = 18659946240.

The previous prime is 21210311077. The next prime is 21210311113. The reversal of 21210311111 is 11111301212.

It is a cyclic number.

It is not a de Polignac number, because 21210311111 - 2¹⁴ = 21210294727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210311113) 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, 10462880 + ... + 10464906.

It is an arithmetic number, because the mean of its divisors is an integer number (746908344).

Almost surely, 2^21210311111 is an apocalyptic number.

21210311111 is a deficient number, since it is larger than the sum of its proper divisors (2690755897).

21210311111 is a wasteful number, since it uses less digits than its factorization.

21210311111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2351.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 21210311111 its reverse (11111301212), we get a palindrome (32321612323).

The spelling of 21210311111 in words is "twenty-one billion, two hundred ten million, three hundred eleven thousand, one hundred eleven".