21221021222 has 16 divisors (see below), whose sum is σ = 33708195360. Its totient is φ = 9985112448.

The previous prime is 21221021209. The next prime is 21221021251. The reversal of 21221021222 is 22212012212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 21221021222.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 272423 + ... + 341549.

It is an arithmetic number, because the mean of its divisors is an integer number (2106762210).

Almost surely, 2^21221021222 is an apocalyptic number.

21221021222 is a deficient number, since it is larger than the sum of its proper divisors (12487174138).

21221021222 is a wasteful number, since it uses less digits than its factorization.

21221021222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78175.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21221021222 its reverse (22212012212), we get a palindrome (43433033434).

The spelling of 21221021222 in words is "twenty-one billion, two hundred twenty-one million, twenty-one thousand, two hundred twenty-two".