21222021022172 has 12 divisors (see below), whose sum is σ = 37175198727576. Its totient is φ = 10600535671440.

The previous prime is 21222021022171. The next prime is 21222021022183. The reversal of 21222021022172 is 27122012022212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222021022171) 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 3 ways as a sum of consecutive naturals, for example, 2618705354 + ... + 2618713457.

It is an arithmetic number, because the mean of its divisors is an integer number (3097933227298).

Almost surely, 2^{21222021022172} is an apocalyptic number.

It is an amenable number.

21222021022172 is a deficient number, since it is larger than the sum of its proper divisors (15953177705404).

21222021022172 is a wasteful number, since it uses less digits than its factorization.

21222021022172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5237419828 (or 5237419826 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

Adding to 21222021022172 its reverse (27122012022212), we get a palindrome (48344033044384).

The spelling of 21222021022172 in words is "twenty-one trillion, two hundred twenty-two billion, twenty-one million, twenty-two thousand, one hundred seventy-two".