21634135 has 4 divisors (see below), whose sum is σ = 25960968. Its totient is φ = 17307304.

The previous prime is 21634133. The next prime is 21634139. The reversal of 21634135 is 53143612.

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 21634135 - 2¹ = 21634133 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 (21634133) 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, 2163409 + ... + 2163418.

It is an arithmetic number, because the mean of its divisors is an integer number (6490242).

Almost surely, 2^21634135 is an apocalyptic number.

21634135 is a deficient number, since it is larger than the sum of its proper divisors (4326833).

21634135 is an equidigital number, since it uses as much as digits as its factorization.

21634135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4326832.

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

The square root of 21634135 is about 4651.2509070142. The cubic root of 21634135 is about 278.6419570960.

Adding to 21634135 its reverse (53143612), we get a palindrome (74777747).

The spelling of 21634135 in words is "twenty-one million, six hundred thirty-four thousand, one hundred thirty-five".