21211101100021 has 8 divisors (see below), whose sum is σ = 25667214776640. Its totient is φ = 17111476517568.

The previous prime is 21211101099997. The next prime is 21211101100027. The reversal of 21211101100021 is 12000110111212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21211101100021 - 2¹⁵ = 21211101067253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211101099974 and 21211101100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211101100027) 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, 89122273411 + ... + 89122273648.

It is an arithmetic number, because the mean of its divisors is an integer number (3208401847080).

Almost surely, 2^{21211101100021} is an apocalyptic number.

It is an amenable number.

21211101100021 is a deficient number, since it is larger than the sum of its proper divisors (4456113676619).

21211101100021 is a wasteful number, since it uses less digits than its factorization.

21211101100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178244547083.

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

Adding to 21211101100021 its reverse (12000110111212), we get a palindrome (33211211211233).

The spelling of 21211101100021 in words is "twenty-one trillion, two hundred eleven billion, one hundred one million, one hundred thousand, twenty-one".