27981797 has 2 divisors, whose sum is σ = 27981798. Its totient is φ = 27981796.

The previous prime is 27981763. The next prime is 27981829. The reversal of 27981797 is 79718972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23512801 + 4468996 = 4849^2 + 2114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27981797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27981727) 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 as a sum of consecutive naturals, namely, 13990898 + 13990899.

It is an arithmetic number, because the mean of its divisors is an integer number (13990899).

Almost surely, 2^27981797 is an apocalyptic number.

It is an amenable number.

27981797 is a deficient number, since it is larger than the sum of its proper divisors (1).

27981797 is an equidigital number, since it uses as much as digits as its factorization.

27981797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 444528, while the sum is 50.

The square root of 27981797 is about 5289.7823206631. The cubic root of 27981797 is about 303.5930793166.

The spelling of 27981797 in words is "twenty-seven million, nine hundred eighty-one thousand, seven hundred ninety-seven".