21993193 has 4 divisors (see below), whose sum is σ = 22116240. Its totient is φ = 21870148.

The previous prime is 21993187. The next prime is 21993211. The reversal of 21993193 is 39139912.

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 a cyclic number.

It is not a de Polignac number, because 21993193 - 2⁵ = 21993161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21993113) 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, 61255 + ... + 61612.

It is an arithmetic number, because the mean of its divisors is an integer number (5529060).

Almost surely, 2^21993193 is an apocalyptic number.

It is an amenable number.

21993193 is a deficient number, since it is larger than the sum of its proper divisors (123047).

21993193 is a wasteful number, since it uses less digits than its factorization.

21993193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123046.

The product of its digits is 13122, while the sum is 37.

The square root of 21993193 is about 4689.6900750476. The cubic root of 21993193 is about 280.1750308697.

The spelling of 21993193 in words is "twenty-one million, nine hundred ninety-three thousand, one hundred ninety-three".