21031220111 has 8 divisors (see below), whose sum is σ = 22966789248. Its totient is φ = 19099591000.

The previous prime is 21031220107. The next prime is 21031220129. The reversal of 21031220111 is 11102213012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21031220111 - 2² = 21031220107 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 (21031222111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 973835 + ... + 995196.

It is an arithmetic number, because the mean of its divisors is an integer number (2870848656).

Almost surely, 2^21031220111 is an apocalyptic number.

21031220111 is a deficient number, since it is larger than the sum of its proper divisors (1935569137).

21031220111 is a wasteful number, since it uses less digits than its factorization.

21031220111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1970013.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21031220111 its reverse (11102213012), we get a palindrome (32133433123).

It can be divided in two parts, 21031 and 220111, that added together give a palindrome (241142).

The spelling of 21031220111 in words is "twenty-one billion, thirty-one million, two hundred twenty thousand, one hundred eleven".