27991297 has 4 divisors (see below), whose sum is σ = 28017220. Its totient is φ = 27965376.

The previous prime is 27991291. The next prime is 27991303. The reversal of 27991297 is 79219972.

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

It is an interprime number because it is at equal distance from previous prime (27991291) and next prime (27991303).

It can be written as a sum of positive squares in 2 ways, for example, as 15992001 + 11999296 = 3999^2 + 3464^2 .

It is a cyclic number.

It is not a de Polignac number, because 27991297 - 2²³ = 19602689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27991291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11268 + ... + 13525.

It is an arithmetic number, because the mean of its divisors is an integer number (7004305).

Almost surely, 2^27991297 is an apocalyptic number.

It is an amenable number.

27991297 is a deficient number, since it is larger than the sum of its proper divisors (25923).

27991297 is a wasteful number, since it uses less digits than its factorization.

27991297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25922.

The product of its digits is 142884, while the sum is 46.

The square root of 27991297 is about 5290.6802020156. The cubic root of 27991297 is about 303.6274326967.

It can be divided in two parts, 2799 and 1297, that added together give a 12-th power (4096 = 2¹²).

The spelling of 27991297 in words is "twenty-seven million, nine hundred ninety-one thousand, two hundred ninety-seven".