21012221102111 has 4 divisors (see below), whose sum is σ = 21012906977352. Its totient is φ = 21011535226872.

The previous prime is 21012221102101. The next prime is 21012221102113. The reversal of 21012221102111 is 11120112221012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012221102111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21012221102111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012221102113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 342891665 + ... + 342952938.

It is an arithmetic number, because the mean of its divisors is an integer number (5253226744338).

Almost surely, 2^{21012221102111} is an apocalyptic number.

21012221102111 is a deficient number, since it is larger than the sum of its proper divisors (685875241).

21012221102111 is an equidigital number, since it uses as much as digits as its factorization.

21012221102111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685875240.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21012221102111 its reverse (11120112221012), we get a palindrome (32132333323123).

The spelling of 21012221102111 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, one hundred two thousand, one hundred eleven".