21221212121024 has 28 divisors (see below), whose sum is σ = 42113359460184. Its totient is φ = 10609971942144.

The previous prime is 21221212120963. The next prime is 21221212121063. The reversal of 21221212121024 is 42012121212212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8827919 + ... + 10971534.

Almost surely, 2^{21221212121024} is an apocalyptic number.

It is an amenable number.

21221212121024 is a deficient number, since it is larger than the sum of its proper divisors (20892147339160).

21221212121024 is a wasteful number, since it uses less digits than its factorization.

21221212121024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19816212 (or 19816202 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

Adding to 21221212121024 its reverse (42012121212212), we get a palindrome (63233333333236).

The spelling of 21221212121024 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, twenty-four".