21087293 has 8 divisors (see below), whose sum is σ = 22546368. Its totient is φ = 19652544.

The previous prime is 21087289. The next prime is 21087331. The reversal of 21087293 is 39278012.

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

It is not a de Polignac number, because 21087293 - 2² = 21087289 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 (21087203) 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 7 ways as a sum of consecutive naturals, for example, 4271 + ... + 7772.

It is an arithmetic number, because the mean of its divisors is an integer number (2818296).

Almost surely, 2^21087293 is an apocalyptic number.

It is an amenable number.

21087293 is a deficient number, since it is larger than the sum of its proper divisors (1459075).

21087293 is a wasteful number, since it uses less digits than its factorization.

21087293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12163.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21087293 is about 4592.0902647923. The cubic root of 21087293 is about 276.2741665829.

The spelling of 21087293 in words is "twenty-one million, eighty-seven thousand, two hundred ninety-three".