21212220221001 has 16 divisors (see below), whose sum is σ = 31464260560320. Its totient is φ = 14124043042560.

The previous prime is 21212220220973. The next prime is 21212220221053. The reversal of 21212220221001 is 10012202221212.

It is a happy number.

21212220221001 is a `hidden beast` number, since 21 + 212 + 220 + 2 + 210 + 0 + 1 = 666.

It is not a de Polignac number, because 21212220221001 - 2¹¹ = 21212220218953 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21212220221201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 484341720 + ... + 484385513.

It is an arithmetic number, because the mean of its divisors is an integer number (1966516285020).

Almost surely, 2^{21212220221001} is an apocalyptic number.

It is an amenable number.

21212220221001 is a deficient number, since it is larger than the sum of its proper divisors (10252040339319).

21212220221001 is an equidigital number, since it uses as much as digits as its factorization.

21212220221001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968728053 (or 968728047 counting only the distinct ones).

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

Adding to 21212220221001 its reverse (10012202221212), we get a palindrome (31224422442213).

The spelling of 21212220221001 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, two hundred twenty-one thousand, one".