27021721 has 4 divisors (see below), whose sum is σ = 28611252. Its totient is φ = 25432192.

The previous prime is 27021697. The next prime is 27021727. The reversal of 27021721 is 12712072.

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 13801225 + 13220496 = 3715^2 + 3636^2 .

It is a cyclic number.

It is not a de Polignac number, because 27021721 - 2¹¹ = 27019673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 27021692 and 27021701.

It is not an unprimeable number, because it can be changed into a prime (27021727) 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, 794740 + ... + 794773.

It is an arithmetic number, because the mean of its divisors is an integer number (7152813).

Almost surely, 2^27021721 is an apocalyptic number.

It is an amenable number.

27021721 is a deficient number, since it is larger than the sum of its proper divisors (1589531).

27021721 is a wasteful number, since it uses less digits than its factorization.

27021721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1589530.

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 27021721 is about 5198.2421067126. The cubic root of 27021721 is about 300.0804265848.

Adding to 27021721 its reverse (12712072), we get a palindrome (39733793).

The spelling of 27021721 in words is "twenty-seven million, twenty-one thousand, seven hundred twenty-one".