21354503 has 4 divisors (see below), whose sum is σ = 21374208. Its totient is φ = 21334800.

The previous prime is 21354451. The next prime is 21354551. The reversal of 21354503 is 30545312.

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 21354503 - 2⁸ = 21354247 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 (21354103) 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, 8126 + ... + 10427.

It is an arithmetic number, because the mean of its divisors is an integer number (5343552).

Almost surely, 2^21354503 is an apocalyptic number.

21354503 is a deficient number, since it is larger than the sum of its proper divisors (19705).

21354503 is a wasteful number, since it uses less digits than its factorization.

21354503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19704.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21354503 is about 4621.0932689138. The cubic root of 21354503 is about 277.4362183310.

Adding to 21354503 its reverse (30545312), we get a palindrome (51899815).

The spelling of 21354503 in words is "twenty-one million, three hundred fifty-four thousand, five hundred three".