1221000020213 has 4 divisors (see below), whose sum is σ = 1223719397100. Its totient is φ = 1218280643328.

The previous prime is 1221000020209. The next prime is 1221000020263. The reversal of 1221000020213 is 3120200001221.

It is a happy number.

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 510448804849 + 710551215364 = 714457^2 + 842942^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221000020213 - 2² = 1221000020209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221000020263) 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, 1359687770 + ... + 1359688667.

It is an arithmetic number, because the mean of its divisors is an integer number (305929849275).

Almost surely, 2^{1221000020213} is an apocalyptic number.

It is an amenable number.

1221000020213 is a deficient number, since it is larger than the sum of its proper divisors (2719376887).

1221000020213 is an equidigital number, since it uses as much as digits as its factorization.

1221000020213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2719376886.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 1221000020213 its reverse (3120200001221), we get a palindrome (4341200021434).

The spelling of 1221000020213 in words is "one trillion, two hundred twenty-one billion, twenty thousand, two hundred thirteen".