21397367 has 4 divisors (see below), whose sum is σ = 21919296. Its totient is φ = 20875440.

The previous prime is 21397349. The next prime is 21397379. The reversal of 21397367 is 76379312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21397367 - 2⁶ = 21397303 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21397367.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21397867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 260903 + ... + 260984.

It is an arithmetic number, because the mean of its divisors is an integer number (5479824).

Almost surely, 2^21397367 is an apocalyptic number.

21397367 is a deficient number, since it is larger than the sum of its proper divisors (521929).

21397367 is an equidigital number, since it uses as much as digits as its factorization.

21397367 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521928.

The product of its digits is 47628, while the sum is 38.

The square root of 21397367 is about 4625.7288074421. The cubic root of 21397367 is about 277.6217229704.

The spelling of 21397367 in words is "twenty-one million, three hundred ninety-seven thousand, three hundred sixty-seven".