1221808363 has 4 divisors (see below), whose sum is σ = 1261221568. Its totient is φ = 1182395160.

The previous prime is 1221808349. The next prime is 1221808397. The reversal of 1221808363 is 3638081221.

It is a happy number.

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 1221808363 - 2⁵ = 1221808331 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221806363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19706556 + ... + 19706617.

It is an arithmetic number, because the mean of its divisors is an integer number (315305392).

Almost surely, 2^1221808363 is an apocalyptic number.

1221808363 is a deficient number, since it is larger than the sum of its proper divisors (39413205).

1221808363 is an equidigital number, since it uses as much as digits as its factorization.

1221808363 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39413204.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 1221808363 is about 34954.3754485758. The cubic root of 1221808363 is about 1069.0574174965.

Adding to 1221808363 its reverse (3638081221), we get a palindrome (4859889584).

The spelling of 1221808363 in words is "one billion, two hundred twenty-one million, eight hundred eight thousand, three hundred sixty-three".