212105116405 has 24 divisors (see below), whose sum is σ = 318856927032. Its totient is φ = 134255544192.

The previous prime is 212105116393. The next prime is 212105116411. The reversal of 212105116405 is 504611501212.

It can be written as a sum of positive squares in 4 ways, for example, as 18031386961 + 194073729444 = 134281^2 + 440538^2 .

It is not a de Polignac number, because 212105116405 - 2¹¹ = 212105114357 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33294322 + ... + 33300691.

It is an arithmetic number, because the mean of its divisors is an integer number (13285705293).

Almost surely, 2^212105116405 is an apocalyptic number.

It is an amenable number.

212105116405 is a deficient number, since it is larger than the sum of its proper divisors (106751810627).

212105116405 is a wasteful number, since it uses less digits than its factorization.

212105116405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66595045 (or 66595038 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

Adding to 212105116405 its reverse (504611501212), we get a palindrome (716716617617).

It can be divided in two parts, 21210 and 5116405, that added together give a triangular number (5137615 = T₃₂₀₅).

The spelling of 212105116405 in words is "two hundred twelve billion, one hundred five million, one hundred sixteen thousand, four hundred five".