221210200100021 has 6 divisors (see below), whose sum is σ = 243148401762966. Its totient is φ = 201100181909000.

The previous prime is 221210200099979. The next prime is 221210200100041. The reversal of 221210200100021 is 120001002012122.

It can be written as a sum of positive squares in only one way, i.e., 132305780880625 + 88904419219396 = 11502425^2 + 9428914^2 .

It is not a de Polignac number, because 221210200100021 - 2¹⁰ = 221210200098997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221210200099969 and 221210200100005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221210200100041) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 914091735830 + ... + 914091736071.

It is an arithmetic number, because the mean of its divisors is an integer number (40524733627161).

Almost surely, 2^{221210200100021} is an apocalyptic number.

It is an amenable number.

221210200100021 is a deficient number, since it is larger than the sum of its proper divisors (21938201662945).

221210200100021 is a wasteful number, since it uses less digits than its factorization.

221210200100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1828183471923 (or 1828183471912 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 221210200100021 its reverse (120001002012122), we get a palindrome (341211202112143).

The spelling of 221210200100021 in words is "two hundred twenty-one trillion, two hundred ten billion, two hundred million, one hundred thousand, twenty-one".