21284383 has 4 divisors (see below), whose sum is σ = 21971008. Its totient is φ = 20597760.

The previous prime is 21284381. The next prime is 21284387. The reversal of 21284383 is 38348212.

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 21284383 - 2¹ = 21284381 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 686593 = 21284383 / (2 + 1 + 2 + 8 + 4 + 3 + 8 + 3).

It is the 4614-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284381) by changing a digit.

It is a nontrivial repunit in base 4613.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 343266 + ... + 343327.

It is an arithmetic number, because the mean of its divisors is an integer number (5492752).

Almost surely, 2^21284383 is an apocalyptic number.

21284383 is a deficient number, since it is larger than the sum of its proper divisors (686625).

21284383 is an equidigital number, since it uses as much as digits as its factorization.

21284383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686624.

The product of its digits is 9216, while the sum is 31.

The square root of 21284383 is about 4613.5000812832. The cubic root of 21284383 is about 277.1322206289.

The spelling of 21284383 in words is "twenty-one million, two hundred eighty-four thousand, three hundred eighty-three".