1221878427563 has 8 divisors (see below), whose sum is σ = 1242687784560. Its totient is φ = 1201072389120.

The previous prime is 1221878427551. The next prime is 1221878427569. The reversal of 1221878427563 is 3657248781221.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1221878427563 - 2¹⁰ = 1221878426539 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221878427499 and 1221878427508.

It is not an unprimeable number, because it can be changed into a prime (1221878427569) 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 7 ways as a sum of consecutive naturals, for example, 81278 + ... + 1565363.

It is an arithmetic number, because the mean of its divisors is an integer number (155335973070).

Almost surely, 2^{1221878427563} is an apocalyptic number.

1221878427563 is a deficient number, since it is larger than the sum of its proper divisors (20809356997).

1221878427563 is a wasteful number, since it uses less digits than its factorization.

1221878427563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659277.

The product of its digits is 9031680, while the sum is 56.

The spelling of 1221878427563 in words is "one trillion, two hundred twenty-one billion, eight hundred seventy-eight million, four hundred twenty-seven thousand, five hundred sixty-three".