1221355618675 has 24 divisors (see below), whose sum is σ = 1525090446000. Its totient is φ = 970243505280.

The previous prime is 1221355618631. The next prime is 1221355618741. The reversal of 1221355618675 is 5768165531221.

It is a happy number.

It is not a de Polignac number, because 1221355618675 - 2⁷ = 1221355618547 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13203736 + ... + 13295914.

It is an arithmetic number, because the mean of its divisors is an integer number (63545435250).

Almost surely, 2^{1221355618675} is an apocalyptic number.

1221355618675 is a deficient number, since it is larger than the sum of its proper divisors (303734827325).

1221355618675 is a wasteful number, since it uses less digits than its factorization.

1221355618675 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95895 (or 95890 counting only the distinct ones).

The product of its digits is 3024000, while the sum is 52.

The spelling of 1221355618675 in words is "one trillion, two hundred twenty-one billion, three hundred fifty-five million, six hundred eighteen thousand, six hundred seventy-five".