1221231306563 has 4 divisors (see below), whose sum is σ = 1221417675288. Its totient is φ = 1221044937840.

The previous prime is 1221231306557. The next prime is 1221231306601. The reversal of 1221231306563 is 3656031321221.

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 1221231306563 - 2¹⁸ = 1221231044419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221231306263) 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, 93174533 + ... + 93187638.

It is an arithmetic number, because the mean of its divisors is an integer number (305354418822).

Almost surely, 2^{1221231306563} is an apocalyptic number.

1221231306563 is a deficient number, since it is larger than the sum of its proper divisors (186368725).

1221231306563 is an equidigital number, since it uses as much as digits as its factorization.

1221231306563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186368724.

The product of its (nonzero) digits is 38880, while the sum is 35.

Adding to 1221231306563 its reverse (3656031321221), we get a palindrome (4877262627784).

The spelling of 1221231306563 in words is "one trillion, two hundred twenty-one billion, two hundred thirty-one million, three hundred six thousand, five hundred sixty-three".