27940721 has 4 divisors (see below), whose sum is σ = 28622244. Its totient is φ = 27259200.

The previous prime is 27940691. The next prime is 27940723. The reversal of 27940721 is 12704972.

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 12816400 + 15124321 = 3580^2 + 3889^2 .

It is a cyclic number.

It is not a de Polignac number, because 27940721 - 2⁶ = 27940657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27940723) 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, 340700 + ... + 340781.

It is an arithmetic number, because the mean of its divisors is an integer number (7155561).

Almost surely, 2^27940721 is an apocalyptic number.

It is an amenable number.

27940721 is a deficient number, since it is larger than the sum of its proper divisors (681523).

27940721 is an equidigital number, since it uses as much as digits as its factorization.

27940721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681522.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 27940721 is about 5285.8983153292. The cubic root of 27940721 is about 303.4444529758. Note that the first 4 decimals are identical.

The spelling of 27940721 in words is "twenty-seven million, nine hundred forty thousand, seven hundred twenty-one".