21386197 has 12 divisors (see below), whose sum is σ = 25116480. Its totient is φ = 18155256.

The previous prime is 21386149. The next prime is 21386203. The reversal of 21386197 is 79168312.

It is a de Polignac number, because none of the positive numbers 2^k-21386197 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 (21386117) 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 11 ways as a sum of consecutive naturals, for example, 3204 + ... + 7282.

It is an arithmetic number, because the mean of its divisors is an integer number (2093040).

Almost surely, 2^21386197 is an apocalyptic number.

It is an amenable number.

21386197 is a deficient number, since it is larger than the sum of its proper divisors (3730283).

21386197 is a wasteful number, since it uses less digits than its factorization.

21386197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4200 (or 4193 counting only the distinct ones).

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

The square root of 21386197 is about 4624.5212725211. The cubic root of 21386197 is about 277.5734058977.

The spelling of 21386197 in words is "twenty-one million, three hundred eighty-six thousand, one hundred ninety-seven".