21101101010221 has 4 divisors (see below), whose sum is σ = 21102561611712. Its totient is φ = 21099640408732.

The previous prime is 21101101010149. The next prime is 21101101010237. The reversal of 21101101010221 is 12201010110112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21101101010221 - 2¹³ = 21101101002029 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 (21101101010021) 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 3 ways as a sum of consecutive naturals, for example, 730279075 + ... + 730307968.

It is an arithmetic number, because the mean of its divisors is an integer number (5275640402928).

Almost surely, 2^{21101101010221} is an apocalyptic number.

It is an amenable number.

21101101010221 is a deficient number, since it is larger than the sum of its proper divisors (1460601491).

21101101010221 is a wasteful number, since it uses less digits than its factorization.

21101101010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1460601490.

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

Adding to 21101101010221 its reverse (12201010110112), we get a palindrome (33302111120333).

The spelling of 21101101010221 in words is "twenty-one trillion, one hundred one billion, one hundred one million, ten thousand, two hundred twenty-one".