211616605 has 4 divisors (see below), whose sum is σ = 253939932. Its totient is φ = 169293280.

The previous prime is 211616599. The next prime is 211616609. The reversal of 211616605 is 506616112.

211616605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 32752729 + 178863876 = 5723^2 + 13374^2 .

It is not a de Polignac number, because 211616605 - 2⁷ = 211616477 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 (211616609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21161656 + ... + 21161665.

It is an arithmetic number, because the mean of its divisors is an integer number (63484983).

Almost surely, 2^211616605 is an apocalyptic number.

It is an amenable number.

211616605 is a deficient number, since it is larger than the sum of its proper divisors (42323327).

211616605 is an equidigital number, since it uses as much as digits as its factorization.

211616605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42323326.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 211616605 is about 14547.0479823227. The cubic root of 211616605 is about 595.9135320784.

It can be divided in two parts, 2116 and 16605, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 211616605 in words is "two hundred eleven million, six hundred sixteen thousand, six hundred five".