21155424503 has 16 divisors (see below), whose sum is σ = 21623397120. Its totient is φ = 20691384000.

The previous prime is 21155424497. The next prime is 21155424517. The reversal of 21155424503 is 30542455112.

It is a cyclic number.

It is not a de Polignac number, because 21155424503 - 2⁸ = 21155424247 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21155424503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155424523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19284251 + ... + 19285347.

It is an arithmetic number, because the mean of its divisors is an integer number (1351462320).

Almost surely, 2^21155424503 is an apocalyptic number.

21155424503 is a deficient number, since it is larger than the sum of its proper divisors (467972617).

21155424503 is a wasteful number, since it uses less digits than its factorization.

21155424503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2518.

The product of its (nonzero) digits is 24000, while the sum is 32.

Adding to 21155424503 its reverse (30542455112), we get a palindrome (51697879615).

The spelling of 21155424503 in words is "twenty-one billion, one hundred fifty-five million, four hundred twenty-four thousand, five hundred three".