27663561 has 24 divisors (see below), whose sum is σ = 41637960. Its totient is φ = 17683200.

The previous prime is 27663553. The next prime is 27663611. The reversal of 27663561 is 16536672.

It can be written as a sum of positive squares in 4 ways, for example, as 571536 + 27092025 = 756^2 + 5205^2 .

It is not a de Polignac number, because 27663561 - 2³ = 27663553 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27663541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21895 + ... + 23123.

It is an arithmetic number, because the mean of its divisors is an integer number (1734915).

Almost surely, 2^27663561 is an apocalyptic number.

It is an amenable number.

27663561 is a deficient number, since it is larger than the sum of its proper divisors (13974399).

27663561 is a wasteful number, since it uses less digits than its factorization.

27663561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337 (or 1334 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 27663561 is about 5259.6160506257. The cubic root of 27663561 is about 302.4377705929.

It can be divided in two parts, 27663 and 561, that added together give a square (28224 = 168²).

The spelling of 27663561 in words is "twenty-seven million, six hundred sixty-three thousand, five hundred sixty-one".