21213727 has 8 divisors (see below), whose sum is σ = 21914064. Its totient is φ = 20524608.

The previous prime is 21213719. The next prime is 21213781. The reversal of 21213727 is 72731212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21213727 - 2³ = 21213719 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 (21213707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1128 + ... + 6610.

It is an arithmetic number, because the mean of its divisors is an integer number (2739258).

Almost surely, 2^21213727 is an apocalyptic number.

21213727 is a deficient number, since it is larger than the sum of its proper divisors (700337).

21213727 is an equidigital number, since it uses as much as digits as its factorization.

21213727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5609.

The product of its digits is 1176, while the sum is 25.

The square root of 21213727 is about 4605.8361890106. The cubic root of 21213727 is about 276.8252230612.

Adding to 21213727 its reverse (72731212), we get a palindrome (93944939).

The spelling of 21213727 in words is "twenty-one million, two hundred thirteen thousand, seven hundred twenty-seven".