27638729 has 2 divisors, whose sum is σ = 27638730. Its totient is φ = 27638728.

The previous prime is 27638717. The next prime is 27638731. The reversal of 27638729 is 92783672.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27583504 + 55225 = 5252^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 27638729 - 2⁴ = 27638713 is a prime.

It is a super-3 number, since 3×27638729³ (a number of 23 digits) contains 333 as substring.

It is a Sophie Germain prime.

Together with 27638731, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 27638729.

It is not a weakly prime, because it can be changed into another prime (27638789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13819364 + 13819365.

It is an arithmetic number, because the mean of its divisors is an integer number (13819365).

Almost surely, 2^27638729 is an apocalyptic number.

It is an amenable number.

27638729 is a deficient number, since it is larger than the sum of its proper divisors (1).

27638729 is an equidigital number, since it uses as much as digits as its factorization.

27638729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 44.

The square root of 27638729 is about 5257.2548920516. The cubic root of 27638729 is about 302.3472497933.

The spelling of 27638729 in words is "twenty-seven million, six hundred thirty-eight thousand, seven hundred twenty-nine".