27939781 has 4 divisors (see below), whose sum is σ = 27953100. Its totient is φ = 27926464.

The previous prime is 27939767. The next prime is 27939797. The reversal of 27939781 is 18793972.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21538881 + 6400900 = 4641^2 + 2530^2 .

It is a cyclic number.

It is not a de Polignac number, because 27939781 - 2²¹ = 25842629 is a prime.

It is a super-2 number, since 2×27939781² = 1561262724655922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27939701) 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 3 ways as a sum of consecutive naturals, for example, 2746 + ... + 7963.

It is an arithmetic number, because the mean of its divisors is an integer number (6988275).

Almost surely, 2^27939781 is an apocalyptic number.

It is an amenable number.

27939781 is a deficient number, since it is larger than the sum of its proper divisors (13319).

27939781 is a wasteful number, since it uses less digits than its factorization.

27939781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13318.

The product of its digits is 190512, while the sum is 46.

The square root of 27939781 is about 5285.8093987582. The cubic root of 27939781 is about 303.4410500454.

The spelling of 27939781 in words is "twenty-seven million, nine hundred thirty-nine thousand, seven hundred eighty-one".