1221013010221 has 4 divisors (see below), whose sum is σ = 1223004875452. Its totient is φ = 1219021144992.

The previous prime is 1221013010219. The next prime is 1221013010227. The reversal of 1221013010221 is 1220103101221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4434894025 + 1216578116196 = 66595^2 + 1102986^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221013010221 - 2¹ = 1221013010219 is a prime.

It is a super-2 number, since 2×1221013010221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221013010195 and 1221013010204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221013010227) 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, 995931696 + ... + 995932921.

It is an arithmetic number, because the mean of its divisors is an integer number (305751218863).

Almost surely, 2^{1221013010221} is an apocalyptic number.

It is an amenable number.

1221013010221 is a deficient number, since it is larger than the sum of its proper divisors (1991865231).

1221013010221 is an equidigital number, since it uses as much as digits as its factorization.

1221013010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1991865230.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 1221013010221 its reverse (1220103101221), we get a palindrome (2441116111442).

The spelling of 1221013010221 in words is "one trillion, two hundred twenty-one billion, thirteen million, ten thousand, two hundred twenty-one".