1221221210213 has 4 divisors (see below), whose sum is σ = 1221245510880. Its totient is φ = 1221196909548.

The previous prime is 1221221210173. The next prime is 1221221210239. The reversal of 1221221210213 is 3120121221221.

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 not a de Polignac number, because 1221221210213 - 2¹⁶ = 1221221144677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221210113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12074795 + ... + 12175512.

It is an arithmetic number, because the mean of its divisors is an integer number (305311377720).

Almost surely, 2^{1221221210213} is an apocalyptic number.

It is an amenable number.

1221221210213 is a deficient number, since it is larger than the sum of its proper divisors (24300667).

1221221210213 is an equidigital number, since it uses as much as digits as its factorization.

1221221210213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24300666.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 1221221210213 its reverse (3120121221221), we get a palindrome (4341342431434).

The spelling of 1221221210213 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred ten thousand, two hundred thirteen".