21327457 has 4 divisors (see below), whose sum is σ = 21420820. Its totient is φ = 21234096.

The previous prime is 21327451. The next prime is 21327511. The reversal of 21327457 is 75472312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12559936 + 8767521 = 3544^2 + 2961^2 .

It is a cyclic number.

It is not a de Polignac number, because 21327457 - 2¹⁹ = 20803169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21327451) 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, 46338 + ... + 46795.

It is an arithmetic number, because the mean of its divisors is an integer number (5355205).

Almost surely, 2^21327457 is an apocalyptic number.

It is an amenable number.

21327457 is a deficient number, since it is larger than the sum of its proper divisors (93363).

21327457 is an equidigital number, since it uses as much as digits as its factorization.

21327457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93362.

The product of its digits is 11760, while the sum is 31.

The square root of 21327457 is about 4618.1659779614. The cubic root of 21327457 is about 277.3190422644.

Adding to 21327457 its reverse (75472312), we get a palindrome (96799769).

The spelling of 21327457 in words is "twenty-one million, three hundred twenty-seven thousand, four hundred fifty-seven".