27690821 has 2 divisors, whose sum is σ = 27690822. Its totient is φ = 27690820.

The previous prime is 27690811. The next prime is 27690863. The reversal of 27690821 is 12809672.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16728100 + 10962721 = 4090^2 + 3311^2 .

It is a cyclic number.

It is not a de Polignac number, because 27690821 - 2⁶ = 27690757 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27690811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13845410 + 13845411.

It is an arithmetic number, because the mean of its divisors is an integer number (13845411).

Almost surely, 2^27690821 is an apocalyptic number.

It is an amenable number.

27690821 is a deficient number, since it is larger than the sum of its proper divisors (1).

27690821 is an equidigital number, since it uses as much as digits as its factorization.

27690821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 27690821 is about 5262.2068564434. The cubic root of 27690821 is about 302.5370798979.

The spelling of 27690821 in words is "twenty-seven million, six hundred ninety thousand, eight hundred twenty-one".