21198323 has 4 divisors (see below), whose sum is σ = 21240480. Its totient is φ = 21156168.

The previous prime is 21198263. The next prime is 21198329. The reversal of 21198323 is 32389112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21198323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21198329) 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, 20315 + ... + 21332.

It is an arithmetic number, because the mean of its divisors is an integer number (5310120).

Almost surely, 2^21198323 is an apocalyptic number.

21198323 is a deficient number, since it is larger than the sum of its proper divisors (42157).

21198323 is an equidigital number, since it uses as much as digits as its factorization.

21198323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42156.

The product of its digits is 2592, while the sum is 29.

The square root of 21198323 is about 4604.1636591242. The cubic root of 21198323 is about 276.7582028046.

The spelling of 21198323 in words is "twenty-one million, one hundred ninety-eight thousand, three hundred twenty-three".