21197273 has 4 divisors (see below), whose sum is σ = 21881088. Its totient is φ = 20513460.

The previous prime is 21197269. The next prime is 21197279. The reversal of 21197273 is 37279112.

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 21197273 - 2² = 21197269 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21197279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341861 + ... + 341922.

It is an arithmetic number, because the mean of its divisors is an integer number (5470272).

Almost surely, 2^21197273 is an apocalyptic number.

It is an amenable number.

21197273 is a deficient number, since it is larger than the sum of its proper divisors (683815).

21197273 is an equidigital number, since it uses as much as digits as its factorization.

21197273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683814.

The product of its digits is 5292, while the sum is 32.

The square root of 21197273 is about 4604.0496304884. The cubic root of 21197273 is about 276.7536332464.

The spelling of 21197273 in words is "twenty-one million, one hundred ninety-seven thousand, two hundred seventy-three".