21010021211111 has 4 divisors (see below), whose sum is σ = 21022387323000. Its totient is φ = 20997655099224.

The previous prime is 21010021211089. The next prime is 21010021211143. The reversal of 21010021211111 is 11111212001012.

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 21010021211111 - 2³⁰ = 21008947469287 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 (21010021219111) 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, 6183053396 + ... + 6183056793.

It is an arithmetic number, because the mean of its divisors is an integer number (5255596830750).

Almost surely, 2^{21010021211111} is an apocalyptic number.

21010021211111 is a deficient number, since it is larger than the sum of its proper divisors (12366111889).

21010021211111 is a wasteful number, since it uses less digits than its factorization.

21010021211111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12366111888.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21010021211111 its reverse (11111212001012), we get a palindrome (32121233212123).

The spelling of 21010021211111 in words is "twenty-one trillion, ten billion, twenty-one million, two hundred eleven thousand, one hundred eleven".