21201110110021 has 16 divisors (see below), whose sum is σ = 21376638771840. Its totient is φ = 21025794000640.

The previous prime is 21201110110009. The next prime is 21201110110073. The reversal of 21201110110021 is 12001101110212.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201110110021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201110109983 and 21201110110010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201110110121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1676368320 + ... + 1676380966.

It is an arithmetic number, because the mean of its divisors is an integer number (1336039923240).

Almost surely, 2^{21201110110021} is an apocalyptic number.

It is an amenable number.

21201110110021 is a deficient number, since it is larger than the sum of its proper divisors (175528661819).

21201110110021 is a wasteful number, since it uses less digits than its factorization.

21201110110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19964.

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

Adding to 21201110110021 its reverse (12001101110212), we get a palindrome (33202211220233).

The spelling of 21201110110021 in words is "twenty-one trillion, two hundred one billion, one hundred ten million, one hundred ten thousand, twenty-one".