21008793 has 16 divisors (see below), whose sum is σ = 31141376. Its totient is φ = 12510720.

The previous prime is 21008773. The next prime is 21008797. The reversal of 21008793 is 39780012.

It is a happy number.

It is not a de Polignac number, because 21008793 - 2⁵ = 21008761 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 21008793.

It is not an unprimeable number, because it can be changed into a prime (21008797) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7480 + ... + 9897.

It is an arithmetic number, because the mean of its divisors is an integer number (1946336).

Almost surely, 2^21008793 is an apocalyptic number.

It is an amenable number.

21008793 is a deficient number, since it is larger than the sum of its proper divisors (10132583).

21008793 is a wasteful number, since it uses less digits than its factorization.

21008793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17424.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21008793 is about 4583.5349895032. The cubic root of 21008793 is about 275.9309189638.

The spelling of 21008793 in words is "twenty-one million, eight thousand, seven hundred ninety-three".