21121220222001 has 18 divisors (see below), whose sum is σ = 32198646899250. Its totient is φ = 13339718032896.

The previous prime is 21121220221967. The next prime is 21121220222009. The reversal of 21121220222001 is 10022202212112.

It is a happy number.

21121220222001 is a `hidden beast` number, since 211 + 212 + 20 + 2 + 220 + 0 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16163005064976 + 4958215157025 = 4020324^2 + 2226705^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21121220222001 is a prime.

It is a super-2 number, since 2×21121220222001² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121220222009) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3250415376 + ... + 3250421873.

It is an arithmetic number, because the mean of its divisors is an integer number (1788813716625).

Almost surely, 2^{21121220222001} is an apocalyptic number.

It is an amenable number.

21121220222001 is a deficient number, since it is larger than the sum of its proper divisors (11077426677249).

21121220222001 is a wasteful number, since it uses less digits than its factorization.

21121220222001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6500837293 (or 6500837271 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21121220222001 its reverse (10022202212112), we get a palindrome (31143422434113).

The spelling of 21121220222001 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty million, two hundred twenty-two thousand, one".