27981647 has 2 divisors, whose sum is σ = 27981648. Its totient is φ = 27981646.

The previous prime is 27981641. The next prime is 27981697. The reversal of 27981647 is 74618972.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 27981647 - 2⁸ = 27981391 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 27981598 and 27981607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27981641) 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, 13990823 + 13990824.

It is an arithmetic number, because the mean of its divisors is an integer number (13990824).

Almost surely, 2^27981647 is an apocalyptic number.

27981647 is the 2828-th centered heptagonal number.

27981647 is a deficient number, since it is larger than the sum of its proper divisors (1).

27981647 is an equidigital number, since it uses as much as digits as its factorization.

27981647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 44.

The square root of 27981647 is about 5289.7681423669. The cubic root of 27981647 is about 303.5925368325.

The spelling of 27981647 in words is "twenty-seven million, nine hundred eighty-one thousand, six hundred forty-seven".