21221212111021 has 8 divisors (see below), whose sum is σ = 22864277381120. Its totient is φ = 19579670317872.

The previous prime is 21221212111007. The next prime is 21221212111063. The reversal of 21221212111021 is 12011121212212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21221212111021 - 2⁷ = 21221212110893 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221212111021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221212111081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 380840301 + ... + 380896018.

It is an arithmetic number, because the mean of its divisors is an integer number (2858034672640).

Almost surely, 2^{21221212111021} is an apocalyptic number.

It is an amenable number.

21221212111021 is a deficient number, since it is larger than the sum of its proper divisors (1643065270099).

21221212111021 is a wasteful number, since it uses less digits than its factorization.

21221212111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761738475.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21221212111021 its reverse (12011121212212), we get a palindrome (33232333323233).

The spelling of 21221212111021 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred eleven thousand, twenty-one".