21222121012 has 6 divisors (see below), whose sum is σ = 37138711778. Its totient is φ = 10611060504.

The previous prime is 21222120989. The next prime is 21222121049. The reversal of 21222121012 is 21012122212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19786923556 + 1435197456 = 140666^2 + 37884^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2652765123 + ... + 2652765130.

Almost surely, 2^21222121012 is an apocalyptic number.

It is an amenable number.

21222121012 is a deficient number, since it is larger than the sum of its proper divisors (15916590766).

21222121012 is a wasteful number, since it uses less digits than its factorization.

21222121012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5305530257 (or 5305530255 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21222121012 its reverse (21012122212), we get a palindrome (42234243224).

The spelling of 21222121012 in words is "twenty-one billion, two hundred twenty-two million, one hundred twenty-one thousand, twelve".