21222120021 has 8 divisors (see below), whose sum is σ = 28465598784. Its totient is φ = 14063360640.

The previous prime is 21222120011. The next prime is 21222120037. The reversal of 21222120021 is 12002122212.

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

It is not a de Polignac number, because 21222120021 - 2⁶ = 21222119957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222120011) 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, 21179260 + ... + 21180261.

It is an arithmetic number, because the mean of its divisors is an integer number (3558199848).

Almost surely, 2^21222120021 is an apocalyptic number.

It is an amenable number.

21222120021 is a deficient number, since it is larger than the sum of its proper divisors (7243478763).

21222120021 is a wasteful number, since it uses less digits than its factorization.

21222120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42359691.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21222120021 its reverse (12002122212), we get a palindrome (33224242233).

The spelling of 21222120021 in words is "twenty-one billion, two hundred twenty-two million, one hundred twenty thousand, twenty-one".