21540103 has 4 divisors (see below), whose sum is σ = 23197048. Its totient is φ = 19883160.

The previous prime is 21540083. The next prime is 21540157. The reversal of 21540103 is 30104512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21540103 - 2⁹ = 21539591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540163) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 828453 + ... + 828478.

It is an arithmetic number, because the mean of its divisors is an integer number (5799262).

Almost surely, 2^21540103 is an apocalyptic number.

21540103 is a deficient number, since it is larger than the sum of its proper divisors (1656945).

21540103 is a wasteful number, since it uses less digits than its factorization.

21540103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1656944.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21540103 is about 4641.1316507938. The cubic root of 21540103 is about 278.2376683275.

Adding to 21540103 its reverse (30104512), we get a palindrome (51644615).

The spelling of 21540103 in words is "twenty-one million, five hundred forty thousand, one hundred three".