21243127 has 4 divisors (see below), whose sum is σ = 21603240. Its totient is φ = 20883016.

The previous prime is 21243077. The next prime is 21243137. The reversal of 21243127 is 72134212.

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 21243127 - 2⁷ = 21242999 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21243098 and 21243107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179968 + ... + 180085.

It is an arithmetic number, because the mean of its divisors is an integer number (5400810).

Almost surely, 2^21243127 is an apocalyptic number.

21243127 is a deficient number, since it is larger than the sum of its proper divisors (360113).

21243127 is an equidigital number, since it uses as much as digits as its factorization.

21243127 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360112.

The product of its digits is 672, while the sum is 22.

The square root of 21243127 is about 4609.0266868396. The cubic root of 21243127 is about 276.9530476010.

Adding to 21243127 its reverse (72134212), we get a palindrome (93377339).

The spelling of 21243127 in words is "twenty-one million, two hundred forty-three thousand, one hundred twenty-seven".