1221443013 has 32 divisors (see below), whose sum is σ = 2018822400. Its totient is φ = 640880640.

The previous prime is 1221443009. The next prime is 1221443021. The reversal of 1221443013 is 3103441221.

It is not a de Polignac number, because 1221443013 - 2² = 1221443009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221443053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27088 + ... + 56361.

It is an arithmetic number, because the mean of its divisors is an integer number (63088200).

Almost surely, 2^1221443013 is an apocalyptic number.

It is an amenable number.

1221443013 is a deficient number, since it is larger than the sum of its proper divisors (797379387).

1221443013 is a wasteful number, since it uses less digits than its factorization.

1221443013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83517.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 1221443013 is about 34949.1489595956. The cubic root of 1221443013 is about 1068.9508489388.

Adding to 1221443013 its reverse (3103441221), we get a palindrome (4324884234).

The spelling of 1221443013 in words is "one billion, two hundred twenty-one million, four hundred forty-three thousand, thirteen".