1221555323345 has 48 divisors (see below), whose sum is σ = 1761771997440. Its totient is φ = 796419161472.

The previous prime is 1221555323333. The next prime is 1221555323371. The reversal of 1221555323345 is 5433235551221.

It is not a de Polignac number, because 1221555323345 - 2⁶ = 1221555323281 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2894471 + ... + 3289539.

It is an arithmetic number, because the mean of its divisors is an integer number (36703583280).

Almost surely, 2^{1221555323345} is an apocalyptic number.

It is an amenable number.

1221555323345 is a deficient number, since it is larger than the sum of its proper divisors (540216674095).

1221555323345 is a wasteful number, since it uses less digits than its factorization.

1221555323345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395294 (or 395271 counting only the distinct ones).

The product of its digits is 540000, while the sum is 41.

The spelling of 1221555323345 in words is "one trillion, two hundred twenty-one billion, five hundred fifty-five million, three hundred twenty-three thousand, three hundred forty-five".