21111200111 has 8 divisors (see below), whose sum is σ = 21154379904. Its totient is φ = 21068057560.

The previous prime is 21111200101. The next prime is 21111200153. The reversal of 21111200111 is 11100211112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111200111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111200092 and 21111200101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111200101) 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, 1310870 + ... + 1326876.

It is an arithmetic number, because the mean of its divisors is an integer number (2644297488).

Almost surely, 2^21111200111 is an apocalyptic number.

21111200111 is a deficient number, since it is larger than the sum of its proper divisors (43179793).

21111200111 is a wasteful number, since it uses less digits than its factorization.

21111200111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18621.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111200111 its reverse (11100211112), we get a palindrome (32211411223).

The spelling of 21111200111 in words is "twenty-one billion, one hundred eleven million, two hundred thousand, one hundred eleven".