1221313122555 has 8 divisors (see below), whose sum is σ = 1954100996112. Its totient is φ = 651366998688.

The previous prime is 1221313122553. The next prime is 1221313122599. The reversal of 1221313122555 is 5552213131221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221313122555 - 2¹ = 1221313122553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221313122553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40710437404 + ... + 40710437433.

It is an arithmetic number, because the mean of its divisors is an integer number (244262624514).

Almost surely, 2^{1221313122555} is an apocalyptic number.

1221313122555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1221313122555 is a deficient number, since it is larger than the sum of its proper divisors (732787873557).

1221313122555 is an equidigital number, since it uses as much as digits as its factorization.

1221313122555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81420874845.

The product of its digits is 18000, while the sum is 33.

Adding to 1221313122555 its reverse (5552213131221), we get a palindrome (6773526253776).

The spelling of 1221313122555 in words is "one trillion, two hundred twenty-one billion, three hundred thirteen million, one hundred twenty-two thousand, five hundred fifty-five".