21101221101001 has 4 divisors (see below), whose sum is σ = 21101230536192. Its totient is φ = 21101211665812.

The previous prime is 21101221100941. The next prime is 21101221101019. The reversal of 21101221101001 is 10010112210112.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21101221101001 - 2¹⁷ = 21101220969929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101221101101) 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, 747096 + ... + 6539158.

It is an arithmetic number, because the mean of its divisors is an integer number (5275307634048).

Almost surely, 2^{21101221101001} is an apocalyptic number.

It is an amenable number.

21101221101001 is a deficient number, since it is larger than the sum of its proper divisors (9435191).

21101221101001 is an equidigital number, since it uses as much as digits as its factorization.

21101221101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9435190.

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

Adding to 21101221101001 its reverse (10010112210112), we get a palindrome (31111333311113).

It can be divided in two parts, 2110122 and 1101001, that added together give a palindrome (3211123).

The spelling of 21101221101001 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, one hundred one thousand, one".