21744197 has 16 divisors (see below), whose sum is σ = 23274240. Its totient is φ = 20284992.

The previous prime is 21744193. The next prime is 21744209. The reversal of 21744197 is 79144712.

It is not a de Polignac number, because 21744197 - 2² = 21744193 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21744193) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 125603 + ... + 125775.

It is an arithmetic number, because the mean of its divisors is an integer number (1454640).

Almost surely, 2^21744197 is an apocalyptic number.

It is an amenable number.

21744197 is a deficient number, since it is larger than the sum of its proper divisors (1530043).

21744197 is a wasteful number, since it uses less digits than its factorization.

21744197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332.

The product of its digits is 14112, while the sum is 35.

The square root of 21744197 is about 4663.0673381370. The cubic root of 21744197 is about 279.1136812289.

The spelling of 21744197 in words is "twenty-one million, seven hundred forty-four thousand, one hundred ninety-seven".