21074539 has 4 divisors (see below), whose sum is σ = 21084624. Its totient is φ = 21064456.

The previous prime is 21074527. The next prime is 21074569. The reversal of 21074539 is 93547012.

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 21074539 - 2¹³ = 21066347 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21074539.

It is not an unprimeable number, because it can be changed into a prime (21074519) 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, 607 + ... + 6520.

It is an arithmetic number, because the mean of its divisors is an integer number (5271156).

Almost surely, 2^21074539 is an apocalyptic number.

21074539 is a deficient number, since it is larger than the sum of its proper divisors (10085).

21074539 is an equidigital number, since it uses as much as digits as its factorization.

21074539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10084.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21074539 is about 4590.7013625371. The cubic root of 21074539 is about 276.2184567084.

The spelling of 21074539 in words is "twenty-one million, seventy-four thousand, five hundred thirty-nine".