1216805434205 has 4 divisors (see below), whose sum is σ = 1460166521052. Its totient is φ = 973444347360.

The previous prime is 1216805434157. The next prime is 1216805434211. The reversal of 1216805434205 is 5024345086121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 856903827481 + 359901606724 = 925691^2 + 599918^2 .

It is not a de Polignac number, because 1216805434205 - 2¹² = 1216805430109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121680543416 + ... + 121680543425.

It is an arithmetic number, because the mean of its divisors is an integer number (365041630263).

Almost surely, 2^{1216805434205} is an apocalyptic number.

It is an amenable number.

1216805434205 is a deficient number, since it is larger than the sum of its proper divisors (243361086847).

1216805434205 is an equidigital number, since it uses as much as digits as its factorization.

1216805434205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243361086846.

The product of its (nonzero) digits is 230400, while the sum is 41.

The spelling of 1216805434205 in words is "one trillion, two hundred sixteen billion, eight hundred five million, four hundred thirty-four thousand, two hundred five".