21092817 has 12 divisors (see below), whose sum is σ = 29401904. Its totient is φ = 13449480.

The previous prime is 21092789. The next prime is 21092821. The reversal of 21092817 is 71829012.

It is not a de Polignac number, because 21092817 - 2¹⁰ = 21091793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21092017) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5059 + ... + 8232.

Almost surely, 2^21092817 is an apocalyptic number.

It is an amenable number.

21092817 is a deficient number, since it is larger than the sum of its proper divisors (8309087).

21092817 is a wasteful number, since it uses less digits than its factorization.

21092817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13340 (or 13317 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21092817 is about 4592.6916944206. The cubic root of 21092817 is about 276.2982886178.

The spelling of 21092817 in words is "twenty-one million, ninety-two thousand, eight hundred seventeen".