27155561 has 4 divisors (see below), whose sum is σ = 27172224. Its totient is φ = 27138900.

The previous prime is 27155549. The next prime is 27155563. The reversal of 27155561 is 16555172.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27155561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (27155563) 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, 5585 + ... + 9246.

It is an arithmetic number, because the mean of its divisors is an integer number (6793056).

Almost surely, 2^27155561 is an apocalyptic number.

It is an amenable number.

27155561 is a deficient number, since it is larger than the sum of its proper divisors (16663).

27155561 is a wasteful number, since it uses less digits than its factorization.

27155561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16662.

The product of its digits is 10500, while the sum is 32.

The square root of 27155561 is about 5211.0997879526. The cubic root of 27155561 is about 300.5750488769.

The spelling of 27155561 in words is "twenty-seven million, one hundred fifty-five thousand, five hundred sixty-one".