21158293 has 6 divisors (see below), whose sum is σ = 22911234. Its totient is φ = 19530576.

The previous prime is 21158273. The next prime is 21158299. The reversal of 21158293 is 39285112.

It can be written as a sum of positive squares in 3 ways, for example, as 528529 + 20629764 = 727^2 + 4542^2 .

It is not a de Polignac number, because 21158293 - 2⁵ = 21158261 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 (21158299) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 62430 + ... + 62767.

It is an arithmetic number, because the mean of its divisors is an integer number (3818539).

Almost surely, 2^21158293 is an apocalyptic number.

It is an amenable number.

21158293 is a deficient number, since it is larger than the sum of its proper divisors (1752941).

21158293 is a wasteful number, since it uses less digits than its factorization.

21158293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125223 (or 125210 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 21158293 is about 4599.8144527796. The cubic root of 21158293 is about 276.5838869456.

The spelling of 21158293 in words is "twenty-one million, one hundred fifty-eight thousand, two hundred ninety-three".