21103533 has 24 divisors (see below), whose sum is σ = 33827040. Its totient is φ = 12569760.

The previous prime is 21103531. The next prime is 21103549. The reversal of 21103533 is 33530112.

It is not a de Polignac number, because 21103533 - 2¹ = 21103531 is a prime.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 4035 + ... + 7647.

It is an arithmetic number, because the mean of its divisors is an integer number (1409460).

Almost surely, 2^21103533 is an apocalyptic number.

It is an amenable number.

21103533 is a deficient number, since it is larger than the sum of its proper divisors (12723507).

21103533 is a wasteful number, since it uses less digits than its factorization.

21103533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3689 (or 3686 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 18.

The square root of 21103533 is about 4593.8581823996. The cubic root of 21103533 is about 276.3450709134.

Adding to 21103533 its reverse (33530112), we get a palindrome (54633645).

The spelling of 21103533 in words is "twenty-one million, one hundred three thousand, five hundred thirty-three".