21897367 has 4 divisors (see below), whose sum is σ = 23049880. Its totient is φ = 20744856.

The previous prime is 21897313. The next prime is 21897371. The reversal of 21897367 is 76379812.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21897367 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 (21897397) 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 3 ways as a sum of consecutive naturals, for example, 576228 + ... + 576265.

It is an arithmetic number, because the mean of its divisors is an integer number (5762470).

Almost surely, 2^21897367 is an apocalyptic number.

21897367 is a deficient number, since it is larger than the sum of its proper divisors (1152513).

21897367 is a wasteful number, since it uses less digits than its factorization.

21897367 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1152512.

The product of its digits is 127008, while the sum is 43.

The square root of 21897367 is about 4679.4622554306. The cubic root of 21897367 is about 279.7675238718.

The spelling of 21897367 in words is "twenty-one million, eight hundred ninety-seven thousand, three hundred sixty-seven".