27815989 has 2 divisors, whose sum is σ = 27815990. Its totient is φ = 27815988.

The previous prime is 27815987. The next prime is 27816001. The reversal of 27815989 is 98951872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 6812100 = 4583^2 + 2610^2 .

It is a cyclic number.

It is not a de Polignac number, because 27815989 - 2¹ = 27815987 is a prime.

Together with 27815987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27815987) 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 as a sum of consecutive naturals, namely, 13907994 + 13907995.

It is an arithmetic number, because the mean of its divisors is an integer number (13907995).

Almost surely, 2^27815989 is an apocalyptic number.

It is an amenable number.

27815989 is a deficient number, since it is larger than the sum of its proper divisors (1).

27815989 is an equidigital number, since it uses as much as digits as its factorization.

27815989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 49.

The square root of 27815989 is about 5274.0865559829. The cubic root of 27815989 is about 302.9922373087.

The spelling of 27815989 in words is "twenty-seven million, eight hundred fifteen thousand, nine hundred eighty-nine".