21104013 has 16 divisors (see below), whose sum is σ = 32907776. Its totient is φ = 11778480.

The previous prime is 21104011. The next prime is 21104029. The reversal of 21104013 is 31040112.

It is a happy number.

It is not a de Polignac number, because 21104013 - 2¹ = 21104011 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21104013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10783 + ... + 12588.

It is an arithmetic number, because the mean of its divisors is an integer number (2056736).

Almost surely, 2^21104013 is an apocalyptic number.

It is an amenable number.

21104013 is a deficient number, since it is larger than the sum of its proper divisors (11803763).

21104013 is a wasteful number, since it uses less digits than its factorization.

21104013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23424.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21104013 is about 4593.9104257702. The cubic root of 21104013 is about 276.3471660543.

Adding to 21104013 its reverse (31040112), we get a palindrome (52144125).

The spelling of 21104013 in words is "twenty-one million, one hundred four thousand, thirteen".