21316873 has 4 divisors (see below), whose sum is σ = 21385728. Its totient is φ = 21248020.

The previous prime is 21316859. The next prime is 21316891. The reversal of 21316873 is 37861312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21316873 - 2¹³ = 21308681 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21317873) 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, 33961 + ... + 34582.

It is an arithmetic number, because the mean of its divisors is an integer number (5346432).

Almost surely, 2^21316873 is an apocalyptic number.

It is an amenable number.

21316873 is a deficient number, since it is larger than the sum of its proper divisors (68855).

21316873 is an equidigital number, since it uses as much as digits as its factorization.

21316873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68854.

The product of its digits is 6048, while the sum is 31.

The square root of 21316873 is about 4617.0199263161. The cubic root of 21316873 is about 277.2731604010.

The spelling of 21316873 in words is "twenty-one million, three hundred sixteen thousand, eight hundred seventy-three".