21313529 has 4 divisors (see below), whose sum is σ = 22567284. Its totient is φ = 20059776.

The previous prime is 21313493. The next prime is 21313531. The reversal of 21313529 is 92531312.

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 19123129 + 2190400 = 4373^2 + 1480^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313529 - 2¹² = 21309433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a zygodrome in base 3.

It is a junction number, because it is equal to n+sod(n) for n = 21313498 and 21313507.

It is not an unprimeable number, because it can be changed into a prime (21313129) 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, 626852 + ... + 626885.

It is an arithmetic number, because the mean of its divisors is an integer number (5641821).

Almost surely, 2^21313529 is an apocalyptic number.

It is an amenable number.

21313529 is a deficient number, since it is larger than the sum of its proper divisors (1253755).

21313529 is a wasteful number, since it uses less digits than its factorization.

21313529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1253754.

The product of its digits is 1620, while the sum is 26.

The square root of 21313529 is about 4616.6577737580. The cubic root of 21313529 is about 277.2586609332.

The spelling of 21313529 in words is "twenty-one million, three hundred thirteen thousand, five hundred twenty-nine".