21220111101001 has 4 divisors (see below), whose sum is σ = 21232615587732. Its totient is φ = 21207606614272.

The previous prime is 21220111100987. The next prime is 21220111101067. The reversal of 21220111101001 is 10010111102212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10095718245376 + 11124392855625 = 3177376^2 + 3335325^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220111101001 - 2¹³ = 21220111092809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220111101601) 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, 6252240820 + ... + 6252244213.

It is an arithmetic number, because the mean of its divisors is an integer number (5308153896933).

Almost surely, 2^{21220111101001} is an apocalyptic number.

It is an amenable number.

21220111101001 is a deficient number, since it is larger than the sum of its proper divisors (12504486731).

21220111101001 is a wasteful number, since it uses less digits than its factorization.

21220111101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12504486730.

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

Adding to 21220111101001 its reverse (10010111102212), we get a palindrome (31230222203213).

The spelling of 21220111101001 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, one hundred one thousand, one".