1221245443 has 4 divisors (see below), whose sum is σ = 1332267768. Its totient is φ = 1110223120.

The previous prime is 1221245429. The next prime is 1221245447. The reversal of 1221245443 is 3445421221.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221245443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221245447) 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, 55511146 + ... + 55511167.

It is an arithmetic number, because the mean of its divisors is an integer number (333066942).

Almost surely, 2^1221245443 is an apocalyptic number.

1221245443 is a deficient number, since it is larger than the sum of its proper divisors (111022325).

1221245443 is a wasteful number, since it uses less digits than its factorization.

1221245443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111022324.

The product of its digits is 7680, while the sum is 28.

The square root of 1221245443 is about 34946.3223100801. The cubic root of 1221245443 is about 1068.8932110998.

Adding to 1221245443 its reverse (3445421221), we get a palindrome (4666666664).

The spelling of 1221245443 in words is "one billion, two hundred twenty-one million, two hundred forty-five thousand, four hundred forty-three".