27981697 has 2 divisors, whose sum is σ = 27981698. Its totient is φ = 27981696.

The previous prime is 27981647. The next prime is 27981727. The reversal of 27981697 is 79618972.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15808576 + 12173121 = 3976^2 + 3489^2 .

It is a cyclic number.

It is not a de Polignac number, because 27981697 - 2¹¹ = 27979649 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 27981697.

It is not a weakly prime, because it can be changed into another prime (27981617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13990848 + 13990849.

It is an arithmetic number, because the mean of its divisors is an integer number (13990849).

Almost surely, 2^27981697 is an apocalyptic number.

It is an amenable number.

27981697 is a deficient number, since it is larger than the sum of its proper divisors (1).

27981697 is an equidigital number, since it uses as much as digits as its factorization.

27981697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 381024, while the sum is 49.

The square root of 27981697 is about 5289.7728684699. The cubic root of 27981697 is about 303.5927176607.

The spelling of 27981697 in words is "twenty-seven million, nine hundred eighty-one thousand, six hundred ninety-seven".