21222021224 has 8 divisors (see below), whose sum is σ = 39791289810. Its totient is φ = 10611010608.

The previous prime is 21222021221. The next prime is 21222021251. The reversal of 21222021224 is 42212022212.

It can be written as a sum of positive squares in only one way, i.e., 12096040324 + 9125980900 = 109982^2 + 95530^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21222021196 and 21222021205.

It is not an unprimeable number, because it can be changed into a prime (21222021221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1326376319 + ... + 1326376334.

Almost surely, 2^21222021224 is an apocalyptic number.

It is an amenable number.

21222021224 is a deficient number, since it is larger than the sum of its proper divisors (18569268586).

21222021224 is a wasteful number, since it uses less digits than its factorization.

21222021224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2652752659 (or 2652752655 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21222021224 its reverse (42212022212), we get a palindrome (63434043436).

The spelling of 21222021224 in words is "twenty-one billion, two hundred twenty-two million, twenty-one thousand, two hundred twenty-four".