21115502424523 has 4 divisors (see below), whose sum is σ = 22739771841808. Its totient is φ = 19491233007240.

The previous prime is 21115502424449. The next prime is 21115502424547. The reversal of 21115502424523 is 32542420551112.

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 21115502424523 - 2³⁷ = 20978063471051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21115502424563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 812134708623 + ... + 812134708648.

It is an arithmetic number, because the mean of its divisors is an integer number (5684942960452).

Almost surely, 2^{21115502424523} is an apocalyptic number.

21115502424523 is a deficient number, since it is larger than the sum of its proper divisors (1624269417285).

21115502424523 is a wasteful number, since it uses less digits than its factorization.

21115502424523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1624269417284.

The product of its (nonzero) digits is 96000, while the sum is 37.

Adding to 21115502424523 its reverse (32542420551112), we get a palindrome (53657922975635).

The spelling of 21115502424523 in words is "twenty-one trillion, one hundred fifteen billion, five hundred two million, four hundred twenty-four thousand, five hundred twenty-three".