1221211010221 has 4 divisors (see below), whose sum is σ = 1233302208444. Its totient is φ = 1209119812000.

The previous prime is 1221211010207. The next prime is 1221211010231. The reversal of 1221211010221 is 1220101121221.

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 1187694554596 + 33516455625 = 1089814^2 + 183075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221211010221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221211010195 and 1221211010204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221211010231) 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, 6045598960 + ... + 6045599161.

It is an arithmetic number, because the mean of its divisors is an integer number (308325552111).

Almost surely, 2^{1221211010221} is an apocalyptic number.

It is an amenable number.

1221211010221 is a deficient number, since it is larger than the sum of its proper divisors (12091198223).

1221211010221 is a wasteful number, since it uses less digits than its factorization.

1221211010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12091198222.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221211010221 its reverse (1220101121221), we get a palindrome (2441312131442).

The spelling of 1221211010221 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, ten thousand, two hundred twenty-one".