21409153 has 4 divisors (see below), whose sum is σ = 21772080. Its totient is φ = 21046228.

The previous prime is 21409151. The next prime is 21409169. The reversal of 21409153 is 35190412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21409153 - 2¹ = 21409151 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21409151) 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, 181375 + ... + 181492.

It is an arithmetic number, because the mean of its divisors is an integer number (5443020).

Almost surely, 2^21409153 is an apocalyptic number.

It is an amenable number.

21409153 is a deficient number, since it is larger than the sum of its proper divisors (362927).

21409153 is an equidigital number, since it uses as much as digits as its factorization.

21409153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362926.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21409153 is about 4627.0025934724. The cubic root of 21409153 is about 277.6726863911.

Adding to 21409153 its reverse (35190412), we get a palindrome (56599565).

The spelling of 21409153 in words is "twenty-one million, four hundred nine thousand, one hundred fifty-three".