21105145 has 8 divisors (see below), whose sum is σ = 26427456. Its totient is φ = 16149936.

The previous prime is 21105121. The next prime is 21105169. The reversal of 21105145 is 54150112.

It is an interprime number because it is at equal distance from previous prime (21105121) and next prime (21105169).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21105145 - 2¹³ = 21096953 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 91647 + ... + 91876.

It is an arithmetic number, because the mean of its divisors is an integer number (3303432).

Almost surely, 2^21105145 is an apocalyptic number.

It is an amenable number.

21105145 is a deficient number, since it is larger than the sum of its proper divisors (5322311).

21105145 is a wasteful number, since it uses less digits than its factorization.

21105145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183551.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21105145 is about 4594.0336306997. The cubic root of 21105145 is about 276.3521069693.

Adding to 21105145 its reverse (54150112), we get a palindrome (75255257).

The spelling of 21105145 in words is "twenty-one million, one hundred five thousand, one hundred forty-five".