21220101111001 has 8 divisors (see below), whose sum is σ = 22852665544520. Its totient is φ = 19587572243712.

The previous prime is 21220101110983. The next prime is 21220101111031. The reversal of 21220101111001 is 10011110102212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2171720952976 + 19048380158025 = 1473676^2 + 4364445^2 .

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 21220101111001 - 2¹⁵ = 21220101078233 is a prime.

It is a super-2 number, since 2×21220101111001² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220101111031) 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 7 ways as a sum of consecutive naturals, for example, 7645920 + ... + 10044913.

It is an arithmetic number, because the mean of its divisors is an integer number (2856583193065).

Almost surely, 2^{21220101111001} is an apocalyptic number.

It is an amenable number.

21220101111001 is a deficient number, since it is larger than the sum of its proper divisors (1632564433519).

21220101111001 is a wasteful number, since it uses less digits than its factorization.

21220101111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17783115.

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

Adding to 21220101111001 its reverse (10011110102212), we get a palindrome (31231211213213).

The spelling of 21220101111001 in words is "twenty-one trillion, two hundred twenty billion, one hundred one million, one hundred eleven thousand, one".