1221220403 has 4 divisors (see below), whose sum is σ = 1315160448. Its totient is φ = 1127280360.

The previous prime is 1221220393. The next prime is 1221220423. The reversal of 1221220403 is 3040221221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221220403 - 2⁴ = 1221220387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221220423) 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, 46970003 + ... + 46970028.

It is an arithmetic number, because the mean of its divisors is an integer number (328790112).

Almost surely, 2^1221220403 is an apocalyptic number.

1221220403 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1221220403 is a deficient number, since it is larger than the sum of its proper divisors (93940045).

1221220403 is an equidigital number, since it uses as much as digits as its factorization.

1221220403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93940044.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1221220403 is about 34945.9640445073. The cubic root of 1221220403 is about 1068.8859056426.

Adding to 1221220403 its reverse (3040221221), we get a palindrome (4261441624).

The spelling of 1221220403 in words is "one billion, two hundred twenty-one million, two hundred twenty thousand, four hundred three".