21716039 has 4 divisors (see below), whose sum is σ = 21750456. Its totient is φ = 21681624.

The previous prime is 21716033. The next prime is 21716047. The reversal of 21716039 is 93061712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21716039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16244 + ... + 17529.

It is an arithmetic number, because the mean of its divisors is an integer number (5437614).

Almost surely, 2^21716039 is an apocalyptic number.

21716039 is a deficient number, since it is larger than the sum of its proper divisors (34417).

21716039 is an equidigital number, since it uses as much as digits as its factorization.

21716039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34416.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 21716039 is about 4660.0471027662. The cubic root of 21716039 is about 278.9931482582.

The spelling of 21716039 in words is "twenty-one million, seven hundred sixteen thousand, thirty-nine".