21191353 has 4 divisors (see below), whose sum is σ = 21212388. Its totient is φ = 21170320.

The previous prime is 21191341. The next prime is 21191369. The reversal of 21191353 is 35319112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11002489 + 10188864 = 3317^2 + 3192^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21191353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21191393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8926 + ... + 11047.

It is an arithmetic number, because the mean of its divisors is an integer number (5303097).

Almost surely, 2^21191353 is an apocalyptic number.

It is an amenable number.

21191353 is a deficient number, since it is larger than the sum of its proper divisors (21035).

21191353 is a wasteful number, since it uses less digits than its factorization.

21191353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21034.

The product of its digits is 810, while the sum is 25.

The square root of 21191353 is about 4603.4066733236. The cubic root of 21191353 is about 276.7278668180.

The spelling of 21191353 in words is "twenty-one million, one hundred ninety-one thousand, three hundred fifty-three".