21243607 has 18 divisors (see below), whose sum is σ = 27170304. Its totient is φ = 16548840.

The previous prime is 21243589. The next prime is 21243611. The reversal of 21243607 is 70634212.

It is not a de Polignac number, because 21243607 - 2¹¹ = 21241559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243637) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4138 + ... + 7720.

Almost surely, 2^21243607 is an apocalyptic number.

21243607 is a deficient number, since it is larger than the sum of its proper divisors (5926697).

21243607 is a wasteful number, since it uses less digits than its factorization.

21243607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3619 (or 3601 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21243607 is about 4609.0787582770. The cubic root of 21243607 is about 276.9551335535.

Adding to 21243607 its reverse (70634212), we get a palindrome (91877819).

The spelling of 21243607 in words is "twenty-one million, two hundred forty-three thousand, six hundred seven".