21012220022201 has 4 divisors (see below), whose sum is σ = 21012414614004. Its totient is φ = 21012025430400.

The previous prime is 21012220022191. The next prime is 21012220022207. The reversal of 21012220022201 is 10222002221012.

It is a happy number.

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 17819204838400 + 3193015183801 = 4221280^2 + 1786901^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012220022201 is a prime.

It is a super-2 number, since 2×21012220022201² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21012220022201.

It is not an unprimeable number, because it can be changed into a prime (21012220022207) 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, 97133840 + ... + 97349921.

It is an arithmetic number, because the mean of its divisors is an integer number (5253103653501).

Almost surely, 2^{21012220022201} is an apocalyptic number.

It is an amenable number.

21012220022201 is a deficient number, since it is larger than the sum of its proper divisors (194591803).

21012220022201 is a wasteful number, since it uses less digits than its factorization.

21012220022201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194591802.

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

Adding to 21012220022201 its reverse (10222002221012), we get a palindrome (31234222243213).

The spelling of 21012220022201 in words is "twenty-one trillion, twelve billion, two hundred twenty million, twenty-two thousand, two hundred one".