21002030021221 has 4 divisors (see below), whose sum is σ = 21026366093952. Its totient is φ = 20977693948492.

The previous prime is 21002030021209. The next prime is 21002030021249. The reversal of 21002030021221 is 12212003020012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21002030021221 - 2¹⁹ = 21002029496933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002030021195 and 21002030021204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002030021201) 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, 12168035071 + ... + 12168036796.

It is an arithmetic number, because the mean of its divisors is an integer number (5256591523488).

Almost surely, 2^{21002030021221} is an apocalyptic number.

It is an amenable number.

21002030021221 is a deficient number, since it is larger than the sum of its proper divisors (24336072731).

21002030021221 is an equidigital number, since it uses as much as digits as its factorization.

21002030021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24336072730.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21002030021221 its reverse (12212003020012), we get a palindrome (33214033041233).

The spelling of 21002030021221 in words is "twenty-one trillion, two billion, thirty million, twenty-one thousand, two hundred twenty-one".