21435413 has 4 divisors (see below), whose sum is σ = 21446028. Its totient is φ = 21424800.

The previous prime is 21435409. The next prime is 21435443. The reversal of 21435413 is 31453412.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 18852964 + 2582449 = 4342^2 + 1607^2 .

It is a cyclic number.

It is not a de Polignac number, because 21435413 - 2² = 21435409 is a prime.

It is a super-3 number, since 3×21435413³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21435443) 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, 1238 + ... + 6663.

It is an arithmetic number, because the mean of its divisors is an integer number (5361507).

Almost surely, 2^21435413 is an apocalyptic number.

It is an amenable number.

21435413 is a deficient number, since it is larger than the sum of its proper divisors (10615).

21435413 is an equidigital number, since it uses as much as digits as its factorization.

21435413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10614.

The product of its digits is 1440, while the sum is 23.

The square root of 21435413 is about 4629.8394140618. The cubic root of 21435413 is about 277.7861690917.

Adding to 21435413 its reverse (31453412), we get a palindrome (52888825).

The spelling of 21435413 in words is "twenty-one million, four hundred thirty-five thousand, four hundred thirteen".