21103145 has 8 divisors (see below), whose sum is σ = 28941504. Its totient is φ = 14470704.

The previous prime is 21103139. The next prime is 21103177. The reversal of 21103145 is 54130112.

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 21103145 - 2⁶ = 21103081 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 (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 301439 + ... + 301508.

It is an arithmetic number, because the mean of its divisors is an integer number (3617688).

Almost surely, 2^21103145 is an apocalyptic number.

It is an amenable number.

21103145 is a deficient number, since it is larger than the sum of its proper divisors (7838359).

21103145 is an equidigital number, since it uses as much as digits as its factorization.

21103145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602959.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21103145 is about 4593.8159519075. The cubic root of 21103145 is about 276.3433773179.

Adding to 21103145 its reverse (54130112), we get a palindrome (75233257).

The spelling of 21103145 in words is "twenty-one million, one hundred three thousand, one hundred forty-five".