1221142213 has 4 divisors (see below), whose sum is σ = 1221432268. Its totient is φ = 1220852160.

The previous prime is 1221142177. The next prime is 1221142229. The reversal of 1221142213 is 3122411221.

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 878411044 + 342731169 = 29638^2 + 18513^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221142213 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 (1221142913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138618 + ... + 147163.

It is an arithmetic number, because the mean of its divisors is an integer number (305358067).

Almost surely, 2^1221142213 is an apocalyptic number.

It is an amenable number.

1221142213 is a deficient number, since it is larger than the sum of its proper divisors (290055).

1221142213 is an equidigital number, since it uses as much as digits as its factorization.

1221142213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290054.

The product of its digits is 192, while the sum is 19.

The square root of 1221142213 is about 34944.8452994143. The cubic root of 1221142213 is about 1068.8630929512.

Adding to 1221142213 its reverse (3122411221), we get a palindrome (4343553434).

The spelling of 1221142213 in words is "one billion, two hundred twenty-one million, one hundred forty-two thousand, two hundred thirteen".