27990691 has 4 divisors (see below), whose sum is σ = 28090584. Its totient is φ = 27890800.

The previous prime is 27990679. The next prime is 27990707. The reversal of 27990691 is 19609972.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 27990691 - 2¹³ = 27982499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27990601) 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, 49525 + ... + 50086.

It is an arithmetic number, because the mean of its divisors is an integer number (7022646).

Almost surely, 2^27990691 is an apocalyptic number.

27990691 is a deficient number, since it is larger than the sum of its proper divisors (99893).

27990691 is an equidigital number, since it uses as much as digits as its factorization.

27990691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99892.

The product of its (nonzero) digits is 61236, while the sum is 43.

The square root of 27990691 is about 5290.6229311868. The cubic root of 27990691 is about 303.6252415447.

It can be divided in two parts, 27990 and 691, that multiplied together give a triangular number (19341090 = T₆₂₁₉).

The spelling of 27990691 in words is "twenty-seven million, nine hundred ninety thousand, six hundred ninety-one".