21211513 has 4 divisors (see below), whose sum is σ = 21704848. Its totient is φ = 20718180.

The previous prime is 21211507. The next prime is 21211577. The reversal of 21211513 is 31511212.

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 21211513 - 2⁵ = 21211481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211013) 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, 246603 + ... + 246688.

It is an arithmetic number, because the mean of its divisors is an integer number (5426212).

Almost surely, 2^21211513 is an apocalyptic number.

It is an amenable number.

21211513 is a deficient number, since it is larger than the sum of its proper divisors (493335).

21211513 is an equidigital number, since it uses as much as digits as its factorization.

21211513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493334.

The product of its digits is 60, while the sum is 16.

The square root of 21211513 is about 4605.5958355027. The cubic root of 21211513 is about 276.8155923103.

Adding to 21211513 its reverse (31511212), we get a palindrome (52722725).

The spelling of 21211513 in words is "twenty-one million, two hundred eleven thousand, five hundred thirteen".