27640405 has 8 divisors (see below), whose sum is σ = 35719992. Its totient is φ = 20411328.

The previous prime is 27640391. The next prime is 27640423. The reversal of 27640405 is 50404672.

It can be written as a sum of positive squares in 4 ways, for example, as 3845521 + 23794884 = 1961^2 + 4878^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 27640405 - 2⁵ = 27640373 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 7 ways as a sum of consecutive naturals, for example, 212554 + ... + 212683.

It is an arithmetic number, because the mean of its divisors is an integer number (4464999).

Almost surely, 2^27640405 is an apocalyptic number.

It is an amenable number.

27640405 is a deficient number, since it is larger than the sum of its proper divisors (8079587).

27640405 is a wasteful number, since it uses less digits than its factorization.

27640405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425255.

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 27640405 is about 5257.4142884121. The cubic root of 27640405 is about 302.3533610699.

The spelling of 27640405 in words is "twenty-seven million, six hundred forty thousand, four hundred five".