21503111023 has 12 divisors (see below), whose sum is σ = 22280145160. Its totient is φ = 20752322976.

The previous prime is 21503111017. The next prime is 21503111027. The reversal of 21503111023 is 32011130512.

It is not a de Polignac number, because 21503111023 - 2⁵ = 21503110991 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 (21503111027) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2549908 + ... + 2558326.

Almost surely, 2^21503111023 is an apocalyptic number.

21503111023 is a deficient number, since it is larger than the sum of its proper divisors (777034137).

21503111023 is an equidigital number, since it uses as much as digits as its factorization.

21503111023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11514 (or 11485 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

Adding to 21503111023 its reverse (32011130512), we get a palindrome (53514241535).

The spelling of 21503111023 in words is "twenty-one billion, five hundred three million, one hundred eleven thousand, twenty-three".