27771981 has 8 divisors (see below), whose sum is σ = 37085664. Its totient is φ = 18486480.

The previous prime is 27771923. The next prime is 27772007. The reversal of 27771981 is 18917772.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 27771981 - 2⁶ = 27771917 is a prime.

It is a super-2 number, since 2×27771981² = 1542565857328722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27771911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4626 + ... + 8771.

It is an arithmetic number, because the mean of its divisors is an integer number (4635708).

Almost surely, 2^27771981 is an apocalyptic number.

It is an amenable number.

27771981 is a deficient number, since it is larger than the sum of its proper divisors (9313683).

27771981 is a wasteful number, since it uses less digits than its factorization.

27771981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14091.

The product of its digits is 49392, while the sum is 42.

The square root of 27771981 is about 5269.9128076278. The cubic root of 27771981 is about 302.8323637845.

The spelling of 27771981 in words is "twenty-seven million, seven hundred seventy-one thousand, nine hundred eighty-one".