1221420043 has 4 divisors (see below), whose sum is σ = 1221495880. Its totient is φ = 1221344208.

The previous prime is 1221420007. The next prime is 1221420047. The reversal of 1221420043 is 3400241221.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221420043 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221420043.

It is not an unprimeable number, because it can be changed into a prime (1221420047) 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, 3105 + ... + 49522.

It is an arithmetic number, because the mean of its divisors is an integer number (305373970).

Almost surely, 2^1221420043 is an apocalyptic number.

1221420043 is a deficient number, since it is larger than the sum of its proper divisors (75837).

1221420043 is an equidigital number, since it uses as much as digits as its factorization.

1221420043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75836.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 1221420043 is about 34948.8203377453. The cubic root of 1221420043 is about 1068.9441481337.

Adding to 1221420043 its reverse (3400241221), we get a palindrome (4621661264).

The spelling of 1221420043 in words is "one billion, two hundred twenty-one million, four hundred twenty thousand, forty-three".