21521103 has 8 divisors (see below), whose sum is σ = 29684400. Its totient is φ = 13852608.

The previous prime is 21521083. The next prime is 21521111. The reversal of 21521103 is 30112512.

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

It is not a de Polignac number, because 21521103 - 2²¹ = 19423951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521183) 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, 123598 + ... + 123771.

It is an arithmetic number, because the mean of its divisors is an integer number (3710550).

Almost surely, 2^21521103 is an apocalyptic number.

21521103 is a deficient number, since it is larger than the sum of its proper divisors (8163297).

21521103 is a wasteful number, since it uses less digits than its factorization.

21521103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247401.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21521103 is about 4639.0842846407. The cubic root of 21521103 is about 278.1558353726.

Adding to 21521103 its reverse (30112512), we get a palindrome (51633615).

The spelling of 21521103 in words is "twenty-one million, five hundred twenty-one thousand, one hundred three".