21008093 has 8 divisors (see below), whose sum is σ = 21821400. Its totient is φ = 20200768.

The previous prime is 21008083. The next prime is 21008149. The reversal of 21008093 is 39080012.

It can be written as a sum of positive squares in 4 ways, for example, as 196249 + 20811844 = 443^2 + 4562^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21008093 - 2⁸ = 21007837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6455 + ... + 9147.

It is an arithmetic number, because the mean of its divisors is an integer number (2727675).

Almost surely, 2^21008093 is an apocalyptic number.

It is an amenable number.

21008093 is a deficient number, since it is larger than the sum of its proper divisors (813307).

21008093 is a wasteful number, since it uses less digits than its factorization.

21008093 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2991.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21008093 is about 4583.4586285904. The cubic root of 21008093 is about 275.9278543138.

The spelling of 21008093 in words is "twenty-one million, eight thousand, ninety-three".