1216043133538 has 16 divisors (see below), whose sum is σ = 1851768743040. Its totient is φ = 598805524800.

The previous prime is 1216043133533. The next prime is 1216043133581. The reversal of 1216043133538 is 8353313406121.

It is a self number, because there is not a number n which added to its sum of digits gives 1216043133538.

It is not an unprimeable number, because it can be changed into a prime (1216043133533) 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, 4528743 + ... + 4789738.

It is an arithmetic number, because the mean of its divisors is an integer number (115735546440).

Almost surely, 2^{1216043133538} is an apocalyptic number.

1216043133538 is a deficient number, since it is larger than the sum of its proper divisors (635725609502).

1216043133538 is an equidigital number, since it uses as much as digits as its factorization.

1216043133538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9319473.

The product of its (nonzero) digits is 155520, while the sum is 40.

Adding to 1216043133538 its reverse (8353313406121), we get a palindrome (9569356539659).

The spelling of 1216043133538 in words is "one trillion, two hundred sixteen billion, forty-three million, one hundred thirty-three thousand, five hundred thirty-eight".