27663981 has 16 divisors (see below), whose sum is σ = 41112000. Its totient is φ = 16443648.

The previous prime is 27663973. The next prime is 27663991. The reversal of 27663981 is 18936672.

It is a happy number.

It is not a de Polignac number, because 27663981 - 2³ = 27663973 is a prime.

It is a super-2 number, since 2×27663981² = 1530591689536722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27663931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13306 + ... + 15243.

It is an arithmetic number, because the mean of its divisors is an integer number (2569500).

Almost surely, 2^27663981 is an apocalyptic number.

It is an amenable number.

27663981 is a deficient number, since it is larger than the sum of its proper divisors (13448019).

27663981 is a wasteful number, since it uses less digits than its factorization.

27663981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28588.

The product of its digits is 108864, while the sum is 42.

The square root of 27663981 is about 5259.6559773430. The cubic root of 27663981 is about 302.4393011650.

The spelling of 27663981 in words is "twenty-seven million, six hundred sixty-three thousand, nine hundred eighty-one".