21324087 has 16 divisors (see below), whose sum is σ = 32327680. Its totient is φ = 13884696.

The previous prime is 21324053. The next prime is 21324089. The reversal of 21324087 is 78042312.

It is not a de Polignac number, because 21324087 - 2⁷ = 21323959 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21324087.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 8023 + ... + 10344.

It is an arithmetic number, because the mean of its divisors is an integer number (2020480).

Almost surely, 2^21324087 is an apocalyptic number.

21324087 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21324087 is a deficient number, since it is larger than the sum of its proper divisors (11003593).

21324087 is a wasteful number, since it uses less digits than its factorization.

21324087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18419 (or 18413 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21324087 is about 4617.8011000908. The cubic root of 21324087 is about 277.3044348908.

Adding to 21324087 its reverse (78042312), we get a palindrome (99366399).

The spelling of 21324087 in words is "twenty-one million, three hundred twenty-four thousand, eighty-seven".