221001122021 has 4 divisors (see below), whose sum is σ = 223189252044. Its totient is φ = 218812992000.

The previous prime is 221001121997. The next prime is 221001122039. The reversal of 221001122021 is 120221100122.

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 156330088996 + 64671033025 = 395386^2 + 254305^2 .

It is a cyclic number.

It is not a de Polignac number, because 221001122021 - 2²² = 220996927717 is a prime.

It is a super-2 number, since 2×221001122021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221001121987 and 221001122005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001122071) 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, 1094064860 + ... + 1094065061.

It is an arithmetic number, because the mean of its divisors is an integer number (55797313011).

Almost surely, 2^221001122021 is an apocalyptic number.

It is an amenable number.

221001122021 is a deficient number, since it is larger than the sum of its proper divisors (2188130023).

221001122021 is a wasteful number, since it uses less digits than its factorization.

221001122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2188130022.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 221001122021 its reverse (120221100122), we get a palindrome (341222222143).

The spelling of 221001122021 in words is "two hundred twenty-one billion, one million, one hundred twenty-two thousand, twenty-one".