21153634 has 8 divisors (see below), whose sum is σ = 31807440. Its totient is φ = 10551156.

The previous prime is 21153623. The next prime is 21153637. The reversal of 21153634 is 43635112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21153599 and 21153608.

It is not an unprimeable number, because it can be changed into a prime (21153637) by changing a digit.

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, 11784 + ... + 13459.

It is an arithmetic number, because the mean of its divisors is an integer number (3975930).

Almost surely, 2^21153634 is an apocalyptic number.

21153634 is a deficient number, since it is larger than the sum of its proper divisors (10653806).

21153634 is a wasteful number, since it uses less digits than its factorization.

21153634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25664.

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

The square root of 21153634 is about 4599.3079914265. The cubic root of 21153634 is about 276.5635844425.

Adding to 21153634 its reverse (43635112), we get a palindrome (64788746).

The spelling of 21153634 in words is "twenty-one million, one hundred fifty-three thousand, six hundred thirty-four".