21434539 has 4 divisors (see below), whose sum is σ = 24496624. Its totient is φ = 18372456.

The previous prime is 21434531. The next prime is 21434579. The reversal of 21434539 is 93543412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21434539 - 2³ = 21434531 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 21434539.

It is not an unprimeable number, because it can be changed into a prime (21434531) 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, 1531032 + ... + 1531045.

It is an arithmetic number, because the mean of its divisors is an integer number (6124156).

Almost surely, 2^21434539 is an apocalyptic number.

21434539 is a deficient number, since it is larger than the sum of its proper divisors (3062085).

21434539 is an equidigital number, since it uses as much as digits as its factorization.

21434539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3062084.

The product of its digits is 12960, while the sum is 31.

The square root of 21434539 is about 4629.7450253767. The cubic root of 21434539 is about 277.7823935885.

The spelling of 21434539 in words is "twenty-one million, four hundred thirty-four thousand, five hundred thirty-nine".