21208873 has 8 divisors (see below), whose sum is σ = 24430592. Its totient is φ = 18035136.

The previous prime is 21208871. The next prime is 21208879. The reversal of 21208873 is 37880212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21208873 - 2¹ = 21208871 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21208871) 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 7 ways as a sum of consecutive naturals, for example, 11040 + ... + 12817.

It is an arithmetic number, because the mean of its divisors is an integer number (3053824).

Almost surely, 2^21208873 is an apocalyptic number.

It is an amenable number.

21208873 is a deficient number, since it is larger than the sum of its proper divisors (3221719).

21208873 is a wasteful number, since it uses less digits than its factorization.

21208873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23991.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 21208873 is about 4605.3092187170. The cubic root of 21208873 is about 276.8041076119.

The spelling of 21208873 in words is "twenty-one million, two hundred eight thousand, eight hundred seventy-three".