27438721 has 4 divisors (see below), whose sum is σ = 27769392. Its totient is φ = 27108052.

The previous prime is 27438709. The next prime is 27438757. The reversal of 27438721 is 12783472.

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 a cyclic number.

It is not a de Polignac number, because 27438721 - 2¹⁷ = 27307649 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27438781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165211 + ... + 165376.

It is an arithmetic number, because the mean of its divisors is an integer number (6942348).

Almost surely, 2^27438721 is an apocalyptic number.

It is an amenable number.

27438721 is a deficient number, since it is larger than the sum of its proper divisors (330671).

27438721 is an equidigital number, since it uses as much as digits as its factorization.

27438721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330670.

The product of its digits is 18816, while the sum is 34.

The square root of 27438721 is about 5238.1982589436. The cubic root of 27438721 is about 301.6161702698.

The spelling of 27438721 in words is "twenty-seven million, four hundred thirty-eight thousand, seven hundred twenty-one".