27642221 has 4 divisors (see below), whose sum is σ = 29268252. Its totient is φ = 26016192.

The previous prime is 27642193. The next prime is 27642227. The reversal of 27642221 is 12224672.

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 9066121 + 18576100 = 3011^2 + 4310^2 .

It is a cyclic number.

It is not a de Polignac number, because 27642221 - 2¹⁰ = 27641197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27642227) 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, 812990 + ... + 813023.

It is an arithmetic number, because the mean of its divisors is an integer number (7317063).

Almost surely, 2^27642221 is an apocalyptic number.

It is an amenable number.

27642221 is a deficient number, since it is larger than the sum of its proper divisors (1626031).

27642221 is a wasteful number, since it uses less digits than its factorization.

27642221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1626030.

The product of its digits is 2688, while the sum is 26.

The square root of 27642221 is about 5257.5869940496. The cubic root of 27642221 is about 302.3599825561.

Adding to 27642221 its reverse (12224672), we get a palindrome (39866893).

The spelling of 27642221 in words is "twenty-seven million, six hundred forty-two thousand, two hundred twenty-one".