2661605 has 16 divisors (see below), whose sum is σ = 3420144. Its totient is φ = 1981440.

The previous prime is 2661569. The next prime is 2661611. The reversal of 2661605 is 5061662.

2661605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 1444 + 2660161 = 38^2 + 1631^2 .

It is not a de Polignac number, because 2661605 - 2⁶ = 2661541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14615 + ... + 14795.

It is an arithmetic number, because the mean of its divisors is an integer number (213759).

2^2661605 is an apocalyptic number.

It is an amenable number.

2661605 is a deficient number, since it is larger than the sum of its proper divisors (758539).

2661605 is a wasteful number, since it uses less digits than its factorization.

2661605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 2661605 is about 1631.4426131495. The cubic root of 2661605 is about 138.5844602070.

Multiplying 2661605 by its sum of digits (26), we get a triangular number (69201730 = T₁₁₇₆₄).

The spelling of 2661605 in words is "two million, six hundred sixty-one thousand, six hundred five".