1216563635541 has 16 divisors (see below), whose sum is σ = 1625335216640. Its totient is φ = 809418225600.

The previous prime is 1216563635531. The next prime is 1216563635629. The reversal of 1216563635541 is 1455363656121.

It is not a de Polignac number, because 1216563635541 - 2²¹ = 1216561538389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216563635531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4878591 + ... + 5121891.

It is an arithmetic number, because the mean of its divisors is an integer number (101583451040).

Almost surely, 2^{1216563635541} is an apocalyptic number.

It is an amenable number.

1216563635541 is a deficient number, since it is larger than the sum of its proper divisors (408771581099).

1216563635541 is a wasteful number, since it uses less digits than its factorization.

1216563635541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246636.

The product of its digits is 1944000, while the sum is 48.

The spelling of 1216563635541 in words is "one trillion, two hundred sixteen billion, five hundred sixty-three million, six hundred thirty-five thousand, five hundred forty-one".