21523015503 has 24 divisors (see below), whose sum is σ = 33955608960. Its totient is φ = 13028654160.

The previous prime is 21523015499. The next prime is 21523015531. The reversal of 21523015503 is 30551032512.

It is a happy number.

21523015503 is a `hidden beast` number, since 2 + 152 + 3 + 0 + 1 + 5 + 503 = 666.

It is not a de Polignac number, because 21523015503 - 2² = 21523015499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523015583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46501 + ... + 212622.

It is an arithmetic number, because the mean of its divisors is an integer number (1414817040).

Almost surely, 2^21523015503 is an apocalyptic number.

21523015503 is a deficient number, since it is larger than the sum of its proper divisors (12432593457).

21523015503 is a wasteful number, since it uses less digits than its factorization.

21523015503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259979 (or 259976 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The spelling of 21523015503 in words is "twenty-one billion, five hundred twenty-three million, fifteen thousand, five hundred three".