27939721 has 4 divisors (see below), whose sum is σ = 29583252. Its totient is φ = 26296192.

The previous prime is 27939713. The next prime is 27939727. The reversal of 27939721 is 12793972.

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 10634121 + 17305600 = 3261^2 + 4160^2 .

It is a cyclic number.

It is not a de Polignac number, because 27939721 - 2³ = 27939713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27939727) 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, 821740 + ... + 821773.

It is an arithmetic number, because the mean of its divisors is an integer number (7395813).

Almost surely, 2^27939721 is an apocalyptic number.

It is an amenable number.

27939721 is a deficient number, since it is larger than the sum of its proper divisors (1643531).

27939721 is a wasteful number, since it uses less digits than its factorization.

27939721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643530.

The product of its digits is 47628, while the sum is 40.

The square root of 27939721 is about 5285.8037231816. The cubic root of 27939721 is about 303.4408328345.

It can be divided in two parts, 279 and 39721, that added together give a square (40000 = 200²).

The spelling of 27939721 in words is "twenty-seven million, nine hundred thirty-nine thousand, seven hundred twenty-one".