1221663535 has 4 divisors (see below), whose sum is σ = 1465996248. Its totient is φ = 977330824.

The previous prime is 1221663529. The next prime is 1221663551. The reversal of 1221663535 is 5353661221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5353661221 = 157 ⋅34099753.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221663535 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221663535.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122166349 + ... + 122166358.

It is an arithmetic number, because the mean of its divisors is an integer number (366499062).

Almost surely, 2^1221663535 is an apocalyptic number.

1221663535 is a deficient number, since it is larger than the sum of its proper divisors (244332713).

1221663535 is an equidigital number, since it uses as much as digits as its factorization.

1221663535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244332712.

The product of its digits is 32400, while the sum is 34.

The square root of 1221663535 is about 34952.3037152060. The cubic root of 1221663535 is about 1069.0151753112.

The spelling of 1221663535 in words is "one billion, two hundred twenty-one million, six hundred sixty-three thousand, five hundred thirty-five".