21868593 has 4 divisors (see below), whose sum is σ = 29158128. Its totient is φ = 14579060.

The previous prime is 21868589. The next prime is 21868597. The reversal of 21868593 is 39586812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21868589) and next prime (21868597).

It is a cyclic number.

It is not a de Polignac number, because 21868593 - 2² = 21868589 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21868597) 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, 3644763 + ... + 3644768.

It is an arithmetic number, because the mean of its divisors is an integer number (7289532).

Almost surely, 2^21868593 is an apocalyptic number.

It is an amenable number.

21868593 is a deficient number, since it is larger than the sum of its proper divisors (7289535).

21868593 is an equidigital number, since it uses as much as digits as its factorization.

21868593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7289534.

The product of its digits is 103680, while the sum is 42.

The square root of 21868593 is about 4676.3867461963. The cubic root of 21868593 is about 279.6449283206.

The spelling of 21868593 in words is "twenty-one million, eight hundred sixty-eight thousand, five hundred ninety-three".