1221143563 has 4 divisors (see below), whose sum is σ = 1223182800. Its totient is φ = 1219104328.

The previous prime is 1221143551. The next prime is 1221143587. The reversal of 1221143563 is 3653411221.

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 1221143563 - 2²⁵ = 1187589131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221143503) 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, 1018720 + ... + 1019917.

It is an arithmetic number, because the mean of its divisors is an integer number (305795700).

Almost surely, 2^1221143563 is an apocalyptic number.

1221143563 is a deficient number, since it is larger than the sum of its proper divisors (2039237).

1221143563 is an equidigital number, since it uses as much as digits as its factorization.

1221143563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2039236.

The product of its digits is 4320, while the sum is 28.

The square root of 1221143563 is about 34944.8646155626. The cubic root of 1221143563 is about 1068.8634868351.

Adding to 1221143563 its reverse (3653411221), we get a palindrome (4874554784).

The spelling of 1221143563 in words is "one billion, two hundred twenty-one million, one hundred forty-three thousand, five hundred sixty-three".