1221210200021 has 4 divisors (see below), whose sum is σ = 1395668800032. Its totient is φ = 1046751600012.

The previous prime is 1221210200003. The next prime is 1221210200047. The reversal of 1221210200021 is 1200020121221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221210200021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221210199969 and 1221210200005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221210203021) 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 3 ways as a sum of consecutive naturals, for example, 87229299995 + ... + 87229300008.

It is an arithmetic number, because the mean of its divisors is an integer number (348917200008).

Almost surely, 2^{1221210200021} is an apocalyptic number.

It is an amenable number.

1221210200021 is a deficient number, since it is larger than the sum of its proper divisors (174458600011).

1221210200021 is an equidigital number, since it uses as much as digits as its factorization.

1221210200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174458600010.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221210200021 its reverse (1200020121221), we get a palindrome (2421230321242).

The spelling of 1221210200021 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, two hundred thousand, twenty-one".