27805861 has 2 divisors, whose sum is σ = 27805862. Its totient is φ = 27805860.

The previous prime is 27805859. The next prime is 27805889. The reversal of 27805861 is 16850872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22743361 + 5062500 = 4769^2 + 2250^2 .

It is a cyclic number.

It is not a de Polignac number, because 27805861 - 2¹ = 27805859 is a prime.

Together with 27805859, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 27805861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27805891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13902930 + 13902931.

It is an arithmetic number, because the mean of its divisors is an integer number (13902931).

Almost surely, 2^27805861 is an apocalyptic number.

It is an amenable number.

27805861 is a deficient number, since it is larger than the sum of its proper divisors (1).

27805861 is an equidigital number, since it uses as much as digits as its factorization.

27805861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 27805861 is about 5273.1263022992. The cubic root of 27805861 is about 302.9554589663.

The spelling of 27805861 in words is "twenty-seven million, eight hundred five thousand, eight hundred sixty-one".