21110013 has 12 divisors (see below), whose sum is σ = 30807868.
Its totient is φ = 13927680.
The previous prime is 21109987. The next prime is 21110027. The reversal of 21110013 is 31001112.
Adding to 21110013 its reverse (31001112), we get a palindrome (52111125).
It can be written as a sum of positive squares in 2 ways, for example, as 12659364 + 8450649 = 3558^2 + 2907^2
It is not a de Polignac number, because 21110013 - 216 = 21044477 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 21109977 and 21110004.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21110093) 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 11 ways as a sum of consecutive naturals, for example, 11218 + ... + 12963.
Almost surely, 221110013 is an apocalyptic number.
It is an amenable number.
21110013 is a deficient number, since it is larger than the sum of its proper divisors (9697855).
21110013 is a wasteful number, since it uses less digits than its factorization.
21110013 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 24284 (or 24281 counting only the distinct ones).
The product of its (nonzero) digits is 6, while the sum is 9.
The square root of 21110013 is about 4594.5634177798.
The cubic root of 21110013 is about 276.3733526361.
The spelling of 21110013 in words is "twenty-one million, one hundred ten thousand, thirteen".