1221246563 has 4 divisors (see below), whose sum is σ = 1223862120. Its totient is φ = 1218631008.

The previous prime is 1221246557. The next prime is 1221246577. The reversal of 1221246563 is 3656421221.

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 1221246563 - 2⁴ = 1221246547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221246503) 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, 1307078 + ... + 1308011.

It is an arithmetic number, because the mean of its divisors is an integer number (305965530).

Almost surely, 2^1221246563 is an apocalyptic number.

1221246563 is a deficient number, since it is larger than the sum of its proper divisors (2615557).

1221246563 is an equidigital number, since it uses as much as digits as its factorization.

1221246563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2615556.

The product of its digits is 17280, while the sum is 32.

The square root of 1221246563 is about 34946.3383346525. The cubic root of 1221246563 is about 1068.8935378592.

Adding to 1221246563 its reverse (3656421221), we get a palindrome (4877667784).

The spelling of 1221246563 in words is "one billion, two hundred twenty-one million, two hundred forty-six thousand, five hundred sixty-three".