21222001202021 has 8 divisors (see below), whose sum is σ = 21257118405144. Its totient is φ = 21186890260480.

The previous prime is 21222001201903. The next prime is 21222001202069. The reversal of 21222001202021 is 12020210022212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8171765476900 + 13050235725121 = 2858630^2 + 3612511^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222001202021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222001202921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5243165 + ... + 8362701.

It is an arithmetic number, because the mean of its divisors is an integer number (2657139800643).

Almost surely, 2^{21222001202021} is an apocalyptic number.

It is an amenable number.

21222001202021 is a deficient number, since it is larger than the sum of its proper divisors (35117203123).

21222001202021 is a wasteful number, since it uses less digits than its factorization.

21222001202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3130791.

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

Adding to 21222001202021 its reverse (12020210022212), we get a palindrome (33242211224233).

The spelling of 21222001202021 in words is "twenty-one trillion, two hundred twenty-two billion, one million, two hundred two thousand, twenty-one".