1221278177243 has 32 divisors (see below), whose sum is σ = 1332858240000. Its totient is φ = 1114599919104.

The previous prime is 1221278177237. The next prime is 1221278177261. The reversal of 1221278177243 is 3427718721221.

It is a cyclic number.

It is not a de Polignac number, because 1221278177243 - 2¹⁰ = 1221278176219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221278177263) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 55408421 + ... + 55430457.

It is an arithmetic number, because the mean of its divisors is an integer number (41651820000).

Almost surely, 2^{1221278177243} is an apocalyptic number.

1221278177243 is a deficient number, since it is larger than the sum of its proper divisors (111580062757).

1221278177243 is a wasteful number, since it uses less digits than its factorization.

1221278177243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22739.

The product of its digits is 526848, while the sum is 47.

The spelling of 1221278177243 in words is "one trillion, two hundred twenty-one billion, two hundred seventy-eight million, one hundred seventy-seven thousand, two hundred forty-three".