27780861 has 4 divisors (see below), whose sum is σ = 37041152. Its totient is φ = 18520572.

The previous prime is 27780853. The next prime is 27780871. The reversal of 27780861 is 16808772.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 27780861 - 2³ = 27780853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27780871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4630141 + ... + 4630146.

It is an arithmetic number, because the mean of its divisors is an integer number (9260288).

Almost surely, 2^27780861 is an apocalyptic number.

It is an amenable number.

27780861 is a deficient number, since it is larger than the sum of its proper divisors (9260291).

27780861 is an equidigital number, since it uses as much as digits as its factorization.

27780861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9260290.

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 27780861 is about 5270.7552589738. The cubic root of 27780861 is about 302.8646368973.

The spelling of 27780861 in words is "twenty-seven million, seven hundred eighty thousand, eight hundred sixty-one".