21144311 has 4 divisors (see below), whose sum is σ = 22388112. Its totient is φ = 19900512.

The previous prime is 21144307. The next prime is 21144323. The reversal of 21144311 is 11344112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21144311 - 2² = 21144307 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1243783 = 21144311 / (2 + 1 + 1 + 4 + 4 + 3 + 1 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21144311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144301) 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, 621875 + ... + 621908.

It is an arithmetic number, because the mean of its divisors is an integer number (5597028).

Almost surely, 2^21144311 is an apocalyptic number.

21144311 is a deficient number, since it is larger than the sum of its proper divisors (1243801).

21144311 is a wasteful number, since it uses less digits than its factorization.

21144311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243800.

The product of its digits is 96, while the sum is 17.

The square root of 21144311 is about 4598.2943576939. The cubic root of 21144311 is about 276.5229486952.

Adding to 21144311 its reverse (11344112), we get a palindrome (32488423).

The spelling of 21144311 in words is "twenty-one million, one hundred forty-four thousand, three hundred eleven".