21530735 has 4 divisors (see below), whose sum is σ = 25836888. Its totient is φ = 17224584.

The previous prime is 21530713. The next prime is 21530741. The reversal of 21530735 is 53703512.

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 21530735 - 2⁶ = 21530671 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, 2153069 + ... + 2153078.

It is an arithmetic number, because the mean of its divisors is an integer number (6459222).

Almost surely, 2^21530735 is an apocalyptic number.

21530735 is a deficient number, since it is larger than the sum of its proper divisors (4306153).

21530735 is an equidigital number, since it uses as much as digits as its factorization.

21530735 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4306152.

The product of its (nonzero) digits is 3150, while the sum is 26.

The square root of 21530735 is about 4640.1223044226. The cubic root of 21530735 is about 278.1973263904.

The spelling of 21530735 in words is "twenty-one million, five hundred thirty thousand, seven hundred thirty-five".