21368587 has 4 divisors (see below), whose sum is σ = 22297680. Its totient is φ = 20439496.

The previous prime is 21368569. The next prime is 21368591. The reversal of 21368587 is 78586312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21368587 - 2¹¹ = 21366539 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21368527) 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 3 ways as a sum of consecutive naturals, for example, 464512 + ... + 464557.

It is an arithmetic number, because the mean of its divisors is an integer number (5574420).

Almost surely, 2^21368587 is an apocalyptic number.

21368587 is a deficient number, since it is larger than the sum of its proper divisors (929093).

21368587 is an equidigital number, since it uses as much as digits as its factorization.

21368587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 929092.

The product of its digits is 80640, while the sum is 40.

The square root of 21368587 is about 4622.6168995494. The cubic root of 21368587 is about 277.4971977100.

The spelling of 21368587 in words is "twenty-one million, three hundred sixty-eight thousand, five hundred eighty-seven".