221020111001 has 4 divisors (see below), whose sum is σ = 221021507892. Its totient is φ = 221018714112.

The previous prime is 221020110979. The next prime is 221020111157. The reversal of 221020111001 is 100111020122.

221020111001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 29439696400 + 191580414601 = 171580^2 + 437699^2 .

It is a cyclic number.

It is not a de Polignac number, because 221020111001 - 2¹⁸ = 221019848857 is a prime.

It is a super-2 number, since 2×221020111001² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221020611001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 425576 + ... + 789401.

It is an arithmetic number, because the mean of its divisors is an integer number (55255376973).

Almost surely, 2^221020111001 is an apocalyptic number.

It is an amenable number.

221020111001 is a deficient number, since it is larger than the sum of its proper divisors (1396891).

221020111001 is a wasteful number, since it uses less digits than its factorization.

221020111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1396890.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 221020111001 its reverse (100111020122), we get a palindrome (321131131123).

The spelling of 221020111001 in words is "two hundred twenty-one billion, twenty million, one hundred eleven thousand, one".