21002002101221 has 8 divisors (see below), whose sum is σ = 21027921598104. Its totient is φ = 20976094863360.

The previous prime is 21002002101187. The next prime is 21002002101263. The reversal of 21002002101221 is 12210120020012.

It can be written as a sum of positive squares in 4 ways, for example, as 13347981873121 + 7654020228100 = 3653489^2 + 2766590^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21002002101221 - 2³⁴ = 20984822232037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002002101196 and 21002002101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002002101271) 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, 366101 + ... + 6491381.

It is an arithmetic number, because the mean of its divisors is an integer number (2628490199763).

Almost surely, 2^{21002002101221} is an apocalyptic number.

It is an amenable number.

21002002101221 is a deficient number, since it is larger than the sum of its proper divisors (25919496883).

21002002101221 is a wasteful number, since it uses less digits than its factorization.

21002002101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6129511.

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

Adding to 21002002101221 its reverse (12210120020012), we get a palindrome (33212122121233).

The spelling of 21002002101221 in words is "twenty-one trillion, two billion, two million, one hundred one thousand, two hundred twenty-one".