21103530 has 32 divisors (see below), whose sum is σ = 57884544. Its totient is φ = 4823616.

The previous prime is 21103519. The next prime is 21103531. The reversal of 21103530 is 3530112.

It is a happy number.

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 (21103531) 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, 50037 + ... + 50456.

It is an arithmetic number, because the mean of its divisors is an integer number (1808892).

Almost surely, 2^21103530 is an apocalyptic number.

21103530 is an abundant number, since it is smaller than the sum of its proper divisors (36781014).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21103530 is a wasteful number, since it uses less digits than its factorization.

21103530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100510.

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

The square root of 21103530 is about 4593.8578558767. The cubic root of 21103530 is about 276.3450578186.

Adding to 21103530 its reverse (3530112), we get a palindrome (24633642).

The spelling of 21103530 in words is "twenty-one million, one hundred three thousand, five hundred thirty".