21435613 has 4 divisors (see below), whose sum is σ = 21632380. Its totient is φ = 21238848.

The previous prime is 21435593. The next prime is 21435643. The reversal of 21435613 is 31653412.

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 16949689 + 4485924 = 4117^2 + 2118^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435613 - 2⁵ = 21435581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21435643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98220 + ... + 98437.

It is an arithmetic number, because the mean of its divisors is an integer number (5408095).

Almost surely, 2^21435613 is an apocalyptic number.

It is an amenable number.

21435613 is a deficient number, since it is larger than the sum of its proper divisors (196767).

21435613 is a wasteful number, since it uses less digits than its factorization.

21435613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196766.

The product of its digits is 2160, while the sum is 25.

The square root of 21435613 is about 4629.8610130327. The cubic root of 21435613 is about 277.7870330368.

It can be divided in two parts, 214356 and 13, that added together give a square (214369 = 463²).

The spelling of 21435613 in words is "twenty-one million, four hundred thirty-five thousand, six hundred thirteen".