27806645 has 16 divisors (see below), whose sum is σ = 35488368. Its totient is φ = 20843520.

The previous prime is 27806627. The next prime is 27806677. The reversal of 27806645 is 54660872.

27806645 = T₇₆₆ + T₇₆₇ + ... + T₈₅₀.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 579121 + 27227524 = 761^2 + 5218^2 .

It is not a de Polignac number, because 27806645 - 2¹⁰ = 27805621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 27806599 and 27806608.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22955 + ... + 24135.

It is an arithmetic number, because the mean of its divisors is an integer number (2218023).

Almost surely, 2^27806645 is an apocalyptic number.

It is an amenable number.

27806645 is a deficient number, since it is larger than the sum of its proper divisors (7681723).

27806645 is a wasteful number, since it uses less digits than its factorization.

27806645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1480.

The product of its (nonzero) digits is 80640, while the sum is 38.

The square root of 27806645 is about 5273.2006409770. The cubic root of 27806645 is about 302.9583062659.

The spelling of 27806645 in words is "twenty-seven million, eight hundred six thousand, six hundred forty-five".