21324081 has 8 divisors (see below), whose sum is σ = 28481824. Its totient is φ = 14191200.

The previous prime is 21324053. The next prime is 21324089. The reversal of 21324081 is 18042312.

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

It is not a de Polignac number, because 21324081 - 2²³ = 12935473 is a prime.

It is a super-2 number, since 2×21324081² = 909432860989122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (21324089) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4111 + ... + 7716.

It is an arithmetic number, because the mean of its divisors is an integer number (3560228).

Almost surely, 2^21324081 is an apocalyptic number.

It is an amenable number.

21324081 is a deficient number, since it is larger than the sum of its proper divisors (7157743).

21324081 is a wasteful number, since it uses less digits than its factorization.

21324081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12431.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21324081 is about 4617.8004504309. The cubic root of 21324081 is about 277.3044088822.

Adding to 21324081 its reverse (18042312), we get a palindrome (39366393).

The spelling of 21324081 in words is "twenty-one million, three hundred twenty-four thousand, eighty-one".