27645991 has 4 divisors (see below), whose sum is σ = 27656512. Its totient is φ = 27635472.

The previous prime is 27645983. The next prime is 27646001. The reversal of 27645991 is 19954672.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 27645991 - 2³ = 27645983 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 (27645491) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2410 + ... + 7816.

It is an arithmetic number, because the mean of its divisors is an integer number (6914128).

Almost surely, 2^27645991 is an apocalyptic number.

27645991 is a deficient number, since it is larger than the sum of its proper divisors (10521).

27645991 is an equidigital number, since it uses as much as digits as its factorization.

27645991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10520.

The product of its digits is 136080, while the sum is 43.

The square root of 27645991 is about 5257.9455113190. The cubic root of 27645991 is about 302.3737277771.

The spelling of 27645991 in words is "twenty-seven million, six hundred forty-five thousand, nine hundred ninety-one".