21011100202111 has 4 divisors (see below), whose sum is σ = 21127183628824. Its totient is φ = 20895016775400.

The previous prime is 21011100202021. The next prime is 21011100202151. The reversal of 21011100202111 is 11120200111012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21011100202111 - 2²¹ = 21011098104959 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011100202091 and 21011100202100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011100202151) 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, 58041713085 + ... + 58041713446.

It is an arithmetic number, because the mean of its divisors is an integer number (5281795907206).

Almost surely, 2^{21011100202111} is an apocalyptic number.

21011100202111 is a deficient number, since it is larger than the sum of its proper divisors (116083426713).

21011100202111 is a wasteful number, since it uses less digits than its factorization.

21011100202111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116083426712.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21011100202111 its reverse (11120200111012), we get a palindrome (32131300313123).

The spelling of 21011100202111 in words is "twenty-one trillion, eleven billion, one hundred million, two hundred two thousand, one hundred eleven".