21634315 has 4 divisors (see below), whose sum is σ = 25961184. Its totient is φ = 17307448.

The previous prime is 21634309. The next prime is 21634337. The reversal of 21634315 is 51343612.

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 21634315 - 2⁹ = 21633803 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21634315.

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, 2163427 + ... + 2163436.

It is an arithmetic number, because the mean of its divisors is an integer number (6490296).

Almost surely, 2^21634315 is an apocalyptic number.

21634315 is a deficient number, since it is larger than the sum of its proper divisors (4326869).

21634315 is an equidigital number, since it uses as much as digits as its factorization.

21634315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4326868.

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

The square root of 21634315 is about 4651.2702566073. The cubic root of 21634315 is about 278.6427298780.

Adding to 21634315 its reverse (51343612), we get a palindrome (72977927).

The spelling of 21634315 in words is "twenty-one million, six hundred thirty-four thousand, three hundred fifteen".