21212220022001 has 12 divisors (see below), whose sum is σ = 22715192839212. Its totient is φ = 19740122671104.

The previous prime is 21212220021973. The next prime is 21212220022121. The reversal of 21212220022001 is 10022002221212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 216991998976 + 20995228023025 = 465824^2 + 4582055^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21212220022001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21212210022001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78629240 + ... + 78898553.

It is an arithmetic number, because the mean of its divisors is an integer number (1892932736601).

Almost surely, 2^{21212220022001} is an apocalyptic number.

It is an amenable number.

21212220022001 is a deficient number, since it is larger than the sum of its proper divisors (1502972817211).

21212220022001 is an equidigital number, since it uses as much as digits as its factorization.

21212220022001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157527988 (or 157527899 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21212220022001 its reverse (10022002221212), we get a palindrome (31234222243213).

The spelling of 21212220022001 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, twenty-two thousand, one".