21101101021 has 16 divisors (see below), whose sum is σ = 28331549568.
Its totient is φ = 15177614400.
The previous prime is 21101101009. The next prime is 21101101027. The reversal of 21101101021 is 12010110112.
Adding to 21101101021 its reverse (12010110112), we get a palindrome (33111211133).
Subtracting from 21101101021 its reverse (12010110112), we obtain a palindrome (9090990909).
It is not a de Polignac number, because 21101101021 - 25 = 21101100989 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 21101100989 and 21101101007.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21101101027) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (23) of ones.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10539010 + ... + 10541011.
It is an arithmetic number, because the mean of its divisors is an integer number (1770721848).
Almost surely, 221101101021 is an apocalyptic number.
It is an amenable number.
21101101021 is a deficient number, since it is larger than the sum of its proper divisors (7230448547).
21101101021 is a wasteful number, since it uses less digits than its factorization.
21101101021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 21080052.
The product of its (nonzero) digits is 4, while the sum is 10.
The spelling of 21101101021 in words is "twenty-one billion, one hundred one million, one hundred one thousand, twenty-one".