21222100021 has 8 divisors (see below), whose sum is σ = 21685307904. Its totient is φ = 20759378640.

The previous prime is 21222099973. The next prime is 21222100087. The reversal of 21222100021 is 12000122212.

It is a happy number.

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 21222100021 - 2⁷ = 21222099893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222099974 and 21222100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222100091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32730 + ... + 208603.

It is an arithmetic number, because the mean of its divisors is an integer number (2710663488).

Almost surely, 2^21222100021 is an apocalyptic number.

It is an amenable number.

21222100021 is a deficient number, since it is larger than the sum of its proper divisors (463207883).

21222100021 is a wasteful number, since it uses less digits than its factorization.

21222100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243251.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21222100021 its reverse (12000122212), we get a palindrome (33222222233).

The spelling of 21222100021 in words is "twenty-one billion, two hundred twenty-two million, one hundred thousand, twenty-one".