21201100222221 has 12 divisors (see below), whose sum is σ = 30628671665020. Its totient is φ = 14131823630400.

The previous prime is 21201100222213. The next prime is 21201100222229. The reversal of 21201100222221 is 12222200110212.

It is a happy number.

21201100222221 is a `hidden beast` number, since 2 + 120 + 1 + 100 + 222 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (21201100222213) and next prime (21201100222229).

It can be written as a sum of positive squares in 2 ways, for example, as 18289401645321 + 2911698576900 = 4276611^2 + 1706370^2 .

It is not a de Polignac number, because 21201100222221 - 2³ = 21201100222213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201100222194 and 21201100222203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201100222229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 186872176 + ... + 186985593.

Almost surely, 2^{21201100222221} is an apocalyptic number.

It is an amenable number.

21201100222221 is a deficient number, since it is larger than the sum of its proper divisors (9427571442799).

21201100222221 is a wasteful number, since it uses less digits than its factorization.

21201100222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373864076 (or 373864073 counting only the distinct ones).

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

Adding to 21201100222221 its reverse (12222200110212), we get a palindrome (33423300332433).

The spelling of 21201100222221 in words is "twenty-one trillion, two hundred one billion, one hundred million, two hundred twenty-two thousand, two hundred twenty-one".