21809103 has 8 divisors (see below), whose sum is σ = 29513088. Its totient is φ = 14322264.

The previous prime is 21809101. The next prime is 21809111. The reversal of 21809103 is 30190812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21809103 - 2¹ = 21809101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21809101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54051 + ... + 54452.

It is an arithmetic number, because the mean of its divisors is an integer number (3689136).

Almost surely, 2^21809103 is an apocalyptic number.

21809103 is a deficient number, since it is larger than the sum of its proper divisors (7703985).

21809103 is a wasteful number, since it uses less digits than its factorization.

21809103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108573.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21809103 is about 4670.0217344248. The cubic root of 21809103 is about 279.3911216417.

Adding to 21809103 its reverse (30190812), we get a palindrome (51999915).

It can be divided in two parts, 21809 and 103, that added together give a palindrome (21912).

The spelling of 21809103 in words is "twenty-one million, eight hundred nine thousand, one hundred three".