20010021212221 has 4 divisors (see below), whose sum is σ = 20010042984832. Its totient is φ = 20009999439612.

The previous prime is 20010021212177. The next prime is 20010021212227. The reversal of 20010021212221 is 12221212001002.

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 a de Polignac number, because none of the positive numbers 2^k-20010021212221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20010021212195 and 20010021212204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20010021212227) 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, 9444045 + ... + 11367058.

It is an arithmetic number, because the mean of its divisors is an integer number (5002510746208).

Almost surely, 2^{20010021212221} is an apocalyptic number.

It is an amenable number.

20010021212221 is a deficient number, since it is larger than the sum of its proper divisors (21772611).

20010021212221 is an equidigital number, since it uses as much as digits as its factorization.

20010021212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21772610.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20010021212221 its reverse (12221212001002), we get a palindrome (32231233213223).

The spelling of 20010021212221 in words is "twenty trillion, ten billion, twenty-one million, two hundred twelve thousand, two hundred twenty-one".