21324289 has 16 divisors (see below), whose sum is σ = 26772480. Its totient is φ = 16560720.

The previous prime is 21324287. The next prime is 21324301. The reversal of 21324289 is 98242312.

It is a cyclic number.

It is not a de Polignac number, because 21324289 - 2¹ = 21324287 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21324289.

It is not an unprimeable number, because it can be changed into a prime (21324283) 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, 427 + ... + 6544.

It is an arithmetic number, because the mean of its divisors is an integer number (1673280).

Almost surely, 2^21324289 is an apocalyptic number.

It is an amenable number.

21324289 is a deficient number, since it is larger than the sum of its proper divisors (5448191).

21324289 is a wasteful number, since it uses less digits than its factorization.

21324289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7020.

The product of its digits is 6912, while the sum is 31.

The square root of 21324289 is about 4617.8229719209. The cubic root of 21324289 is about 277.3053105097.

The spelling of 21324289 in words is "twenty-one million, three hundred twenty-four thousand, two hundred eighty-nine".