21327539 has 4 divisors (see below), whose sum is σ = 21337056. Its totient is φ = 21318024.

The previous prime is 21327533. The next prime is 21327541. The reversal of 21327539 is 93572312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21327539 - 2²⁴ = 4550323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21327533) 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, 662 + ... + 6564.

It is an arithmetic number, because the mean of its divisors is an integer number (5334264).

Almost surely, 2^21327539 is an apocalyptic number.

21327539 is a deficient number, since it is larger than the sum of its proper divisors (9517).

21327539 is an equidigital number, since it uses as much as digits as its factorization.

21327539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9516.

The product of its digits is 11340, while the sum is 32.

The square root of 21327539 is about 4618.1748559361. The cubic root of 21327539 is about 277.3193976769.

The spelling of 21327539 in words is "twenty-one million, three hundred twenty-seven thousand, five hundred thirty-nine".