21513163 has 8 divisors (see below), whose sum is σ = 25379840. Its totient is φ = 17844840.

The previous prime is 21513161. The next prime is 21513181. The reversal of 21513163 is 36131512.

It is a happy number.

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

It is not a de Polignac number, because 21513163 - 2¹ = 21513161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21513161) 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 7 ways as a sum of consecutive naturals, for example, 49353 + ... + 49786.

It is an arithmetic number, because the mean of its divisors is an integer number (3172480).

Almost surely, 2^21513163 is an apocalyptic number.

21513163 is a deficient number, since it is larger than the sum of its proper divisors (3866677).

21513163 is an equidigital number, since it uses as much as digits as its factorization.

21513163 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99177.

The product of its digits is 540, while the sum is 22.

The square root of 21513163 is about 4638.2284333569. The cubic root of 21513163 is about 278.1216235419.

Adding to 21513163 its reverse (36131512), we get a palindrome (57644675).

The spelling of 21513163 in words is "twenty-one million, five hundred thirteen thousand, one hundred sixty-three".