21170493 has 18 divisors (see below), whose sum is σ = 31681754. Its totient is φ = 13622112.

The previous prime is 21170453. The next prime is 21170507. The reversal of 21170493 is 39407112.

21170493 is a `hidden beast` number, since 2 + 1 + 170 + 493 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 5631129 + 15539364 = 2373^2 + 3942^2 .

It is not a de Polignac number, because 21170493 - 2¹⁴ = 21154109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6171 + ... + 8967.

Almost surely, 2^21170493 is an apocalyptic number.

It is an amenable number.

21170493 is a deficient number, since it is larger than the sum of its proper divisors (10511261).

21170493 is a wasteful number, since it uses less digits than its factorization.

21170493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2861 (or 2829 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21170493 is about 4601.1404021177. The cubic root of 21170493 is about 276.6370367133.

The spelling of 21170493 in words is "twenty-one million, one hundred seventy thousand, four hundred ninety-three".