27909997 has 4 divisors (see below), whose sum is σ = 27965340. Its totient is φ = 27854656.

The previous prime is 27909979. The next prime is 27910007. The reversal of 27909997 is 79990972.

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 18783556 + 9126441 = 4334^2 + 3021^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27909997 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 (27909197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26908 + ... + 27925.

It is an arithmetic number, because the mean of its divisors is an integer number (6991335).

Almost surely, 2^27909997 is an apocalyptic number.

It is an amenable number.

27909997 is a deficient number, since it is larger than the sum of its proper divisors (55343).

27909997 is an equidigital number, since it uses as much as digits as its factorization.

27909997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55342.

The product of its (nonzero) digits is 642978, while the sum is 52.

The square root of 27909997 is about 5282.9912928189. The cubic root of 27909997 is about 303.3331882891. Note that the first 3 decimals are identical.

The spelling of 27909997 in words is "twenty-seven million, nine hundred nine thousand, nine hundred ninety-seven".