21197863 has 8 divisors (see below), whose sum is σ = 22446000. Its totient is φ = 19963008.

The previous prime is 21197857. The next prime is 21197867. The reversal of 21197863 is 36879112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21197863 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 (21197867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63 + ... + 6511.

It is an arithmetic number, because the mean of its divisors is an integer number (2805750).

Almost surely, 2^21197863 is an apocalyptic number.

21197863 is a deficient number, since it is larger than the sum of its proper divisors (1248137).

21197863 is a wasteful number, since it uses less digits than its factorization.

21197863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6641.

The product of its digits is 18144, while the sum is 37.

The square root of 21197863 is about 4604.1137040694. The cubic root of 21197863 is about 276.7562009215.

The spelling of 21197863 in words is "twenty-one million, one hundred ninety-seven thousand, eight hundred sixty-three".