21103305 has 16 divisors (see below), whose sum is σ = 35233920. Its totient is φ = 10765568.

The previous prime is 21103301. The next prime is 21103309. The reversal of 21103305 is 50330112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21103301) and next prime (21103309).

It is a cyclic number.

It is not a de Polignac number, because 21103305 - 2² = 21103301 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (21103301) 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, 30240 + ... + 30929.

It is an arithmetic number, because the mean of its divisors is an integer number (2202120).

Almost surely, 2^21103305 is an apocalyptic number.

It is an amenable number.

21103305 is a deficient number, since it is larger than the sum of its proper divisors (14130615).

21103305 is a wasteful number, since it uses less digits than its factorization.

21103305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61200.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21103305 is about 4593.8333665905. The cubic root of 21103305 is about 276.3440757103.

Adding to 21103305 its reverse (50330112), we get a palindrome (71433417).

The spelling of 21103305 in words is "twenty-one million, one hundred three thousand, three hundred five".