27666721 has 2 divisors, whose sum is σ = 27666722. Its totient is φ = 27666720.

The previous prime is 27666671. The next prime is 27666731. The reversal of 27666721 is 12766672.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26378496 + 1288225 = 5136^2 + 1135^2 .

It is a cyclic number.

It is not a de Polignac number, because 27666721 - 2¹¹ = 27664673 is a prime.

It is not a weakly prime, because it can be changed into another prime (27666731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13833360 + 13833361.

It is an arithmetic number, because the mean of its divisors is an integer number (13833361).

Almost surely, 2^27666721 is an apocalyptic number.

It is an amenable number.

27666721 is a deficient number, since it is larger than the sum of its proper divisors (1).

27666721 is an equidigital number, since it uses as much as digits as its factorization.

27666721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 37.

The square root of 27666721 is about 5259.9164442033. The cubic root of 27666721 is about 302.4492859454.

The spelling of 27666721 in words is "twenty-seven million, six hundred sixty-six thousand, seven hundred twenty-one".