21243927 has 16 divisors (see below), whose sum is σ = 29664000. Its totient is φ = 13497792.

The previous prime is 21243913. The next prime is 21243941. The reversal of 21243927 is 72934212.

It is an interprime number because it is at equal distance from previous prime (21243913) and next prime (21243941).

It is not a de Polignac number, because 21243927 - 2¹² = 21239831 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21243894 and 21243903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34123 + ... + 34739.

It is an arithmetic number, because the mean of its divisors is an integer number (1854000).

Almost surely, 2^21243927 is an apocalyptic number.

21243927 is a deficient number, since it is larger than the sum of its proper divisors (8420073).

21243927 is a wasteful number, since it uses less digits than its factorization.

21243927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142.

The product of its digits is 6048, while the sum is 30.

The square root of 21243927 is about 4609.1134722417. The cubic root of 21243927 is about 276.9565241711.

The spelling of 21243927 in words is "twenty-one million, two hundred forty-three thousand, nine hundred twenty-seven".