21534005 has 4 divisors (see below), whose sum is σ = 25840812. Its totient is φ = 17227200.

The previous prime is 21533999. The next prime is 21534031. The reversal of 21534005 is 50043512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4153444 + 17380561 = 2038^2 + 4169^2 .

It is not a de Polignac number, because 21534005 - 2¹⁴ = 21517621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153396 + ... + 2153405.

It is an arithmetic number, because the mean of its divisors is an integer number (6460203).

Almost surely, 2^21534005 is an apocalyptic number.

It is an amenable number.

21534005 is a deficient number, since it is larger than the sum of its proper divisors (4306807).

21534005 is an equidigital number, since it uses as much as digits as its factorization.

21534005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4306806.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21534005 is about 4640.4746524467. The cubic root of 21534005 is about 278.2114095016.

Adding to 21534005 its reverse (50043512), we get a palindrome (71577517).

The spelling of 21534005 in words is "twenty-one million, five hundred thirty-four thousand, five".