21113645 has 16 divisors (see below), whose sum is σ = 29631360. Its totient is φ = 14140224.

The previous prime is 21113639. The next prime is 21113671. The reversal of 21113645 is 54631112.

It is not a de Polignac number, because 21113645 - 2⁴ = 21113629 is a prime.

It is a super-3 number, since 3×21113645³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21113645.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 5510 + ... + 8519.

It is an arithmetic number, because the mean of its divisors is an integer number (1851960).

Almost surely, 2^21113645 is an apocalyptic number.

It is an amenable number.

21113645 is a deficient number, since it is larger than the sum of its proper divisors (8517715).

21113645 is a wasteful number, since it uses less digits than its factorization.

21113645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14084.

The product of its digits is 720, while the sum is 23.

The square root of 21113645 is about 4594.9586505212. The cubic root of 21113645 is about 276.3892018361.

Adding to 21113645 its reverse (54631112), we get a palindrome (75744757).

The spelling of 21113645 in words is "twenty-one million, one hundred thirteen thousand, six hundred forty-five".