11500203121 has 9 divisors (see below), whose sum is σ = 12642015883. Its totient is φ = 10453657720.

The previous prime is 11500203109. The next prime is 11500203133. The reversal of 11500203121 is 12130200511.

The square root of 11500203121 is 107239.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (11500203109) and next prime (11500203133).

It can be written as a sum of positive squares in only one way, i.e., 1655594721 + 9844608400 = 40689^2 + 99220^2 .

It is a de Polignac number, because none of the positive numbers 2^k-11500203121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11500203095 and 11500203104.

It is not an unprimeable number, because it can be changed into a prime (11500203191) 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 8 ways as a sum of consecutive naturals, for example, 1174755 + ... + 1184503.

Almost surely, 2^11500203121 is an apocalyptic number.

11500203121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11500203121 is the 107239-th square number.

11500203121 is the 53620-th centered octagonal number.

It is an amenable number.

11500203121 is a deficient number, since it is larger than the sum of its proper divisors (1141812762).

11500203121 is an frugal number, since it uses more digits than its factorization.

11500203121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19520 (or 9760 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 16.

Multiplying 11500203121 by its sum of digits (16), we get a square (184003249936 = 428956²).

Adding to 11500203121 its reverse (12130200511), we get a palindrome (23630403632).

The spelling of 11500203121 in words is "eleven billion, five hundred million, two hundred three thousand, one hundred twenty-one".