21284197 has 8 divisors (see below), whose sum is σ = 23968512. Its totient is φ = 18724800.

The previous prime is 21284189. The next prime is 21284227. The reversal of 21284197 is 79148212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21284197 - 2³ = 21284189 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 (21284117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30868 + ... + 31549.

It is an arithmetic number, because the mean of its divisors is an integer number (2996064).

Almost surely, 2^21284197 is an apocalyptic number.

It is an amenable number.

21284197 is a deficient number, since it is larger than the sum of its proper divisors (2684315).

21284197 is a wasteful number, since it uses less digits than its factorization.

21284197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62459.

The product of its digits is 8064, while the sum is 34.

The square root of 21284197 is about 4613.4799230082. The cubic root of 21284197 is about 277.1314133587.

The spelling of 21284197 in words is "twenty-one million, two hundred eighty-four thousand, one hundred ninety-seven".