21324019 has 4 divisors (see below), whose sum is σ = 22059360. Its totient is φ = 20588680.

The previous prime is 21324011. The next prime is 21324031. The reversal of 21324019 is 91042312.

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 21324019 - 2³ = 21324011 is a prime.

It is a super-2 number, since 2×21324019² = 909427572624722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21324011) 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, 367627 + ... + 367684.

It is an arithmetic number, because the mean of its divisors is an integer number (5514840).

Almost surely, 2^21324019 is an apocalyptic number.

21324019 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21324019 is a deficient number, since it is larger than the sum of its proper divisors (735341).

21324019 is an equidigital number, since it uses as much as digits as its factorization.

21324019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 735340.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21324019 is about 4617.7937372732. The cubic root of 21324019 is about 277.3041401267.

The spelling of 21324019 in words is "twenty-one million, three hundred twenty-four thousand, nineteen".