21968593 has 4 divisors (see below), whose sum is σ = 22048180. Its totient is φ = 21889008.

The previous prime is 21968567. The next prime is 21968603. The reversal of 21968593 is 39586912.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12159169 + 9809424 = 3487^2 + 3132^2 .

It is a cyclic number.

It is not a de Polignac number, because 21968593 - 2¹⁷ = 21837521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21968543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39378 + ... + 39931.

It is an arithmetic number, because the mean of its divisors is an integer number (5512045).

Almost surely, 2^21968593 is an apocalyptic number.

It is an amenable number.

21968593 is a deficient number, since it is larger than the sum of its proper divisors (79587).

21968593 is an equidigital number, since it uses as much as digits as its factorization.

21968593 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79586.

The product of its digits is 116640, while the sum is 43.

The square root of 21968593 is about 4687.0665666278. The cubic root of 21968593 is about 280.0705307015.

The spelling of 21968593 in words is "twenty-one million, nine hundred sixty-eight thousand, five hundred ninety-three".