27138781 has 4 divisors (see below), whose sum is σ = 28318752. Its totient is φ = 25958812.

The previous prime is 27138773. The next prime is 27138799. The reversal of 27138781 is 18783172.

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 not a de Polignac number, because 27138781 - 2³ = 27138773 is a prime.

It is a super-2 number, since 2×27138781² = 1473026868331922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 27138781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27138701) 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, 589951 + ... + 589996.

It is an arithmetic number, because the mean of its divisors is an integer number (7079688).

Almost surely, 2^27138781 is an apocalyptic number.

It is an amenable number.

27138781 is a deficient number, since it is larger than the sum of its proper divisors (1179971).

27138781 is a wasteful number, since it uses less digits than its factorization.

27138781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1179970.

The product of its digits is 18816, while the sum is 37.

The square root of 27138781 is about 5209.4895143382. The cubic root of 27138781 is about 300.5131255439.

The spelling of 27138781 in words is "twenty-seven million, one hundred thirty-eight thousand, seven hundred eighty-one".