21011313 has 4 divisors (see below), whose sum is σ = 28015088. Its totient is φ = 14007540.

The previous prime is 21011299. The next prime is 21011317. The reversal of 21011313 is 31311012.

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 not a de Polignac number, because 21011313 - 2¹³ = 21003121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011317) 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, 3501883 + ... + 3501888.

It is an arithmetic number, because the mean of its divisors is an integer number (7003772).

Almost surely, 2^21011313 is an apocalyptic number.

It is an amenable number.

21011313 is a deficient number, since it is larger than the sum of its proper divisors (7003775).

21011313 is an equidigital number, since it uses as much as digits as its factorization.

21011313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7003774.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 21011313 is about 4583.8098782563. The cubic root of 21011313 is about 275.9419511399.

Adding to 21011313 its reverse (31311012), we get a palindrome (52322325).

The spelling of 21011313 in words is "twenty-one million, eleven thousand, three hundred thirteen".