21105732503 has 4 divisors (see below), whose sum is σ = 21106052328. Its totient is φ = 21105412680.

The previous prime is 21105732497. The next prime is 21105732539. The reversal of 21105732503 is 30523750112.

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 21105732503 - 2²⁴ = 21088955287 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 (21105732553) 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, 20288 + ... + 206453.

It is an arithmetic number, because the mean of its divisors is an integer number (5276513082).

Almost surely, 2^21105732503 is an apocalyptic number.

21105732503 is a deficient number, since it is larger than the sum of its proper divisors (319825).

21105732503 is an equidigital number, since it uses as much as digits as its factorization.

21105732503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319824.

The product of its (nonzero) digits is 6300, while the sum is 29.

The spelling of 21105732503 in words is "twenty-one billion, one hundred five million, seven hundred thirty-two thousand, five hundred three".