1115721531 has 6 divisors (see below), whose sum is σ = 1611597780. Its totient is φ = 743814348.

The previous prime is 1115721487. The next prime is 1115721539. The reversal of 1115721531 is 1351275111.

It is not a de Polignac number, because 1115721531 - 2²⁶ = 1048612667 is a prime.

It is a super-2 number, since 2×1115721531² = 2489669069473967922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1115721495 and 1115721504.

It is not an unprimeable number, because it can be changed into a prime (1115721539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 61984521 + ... + 61984538.

It is an arithmetic number, because the mean of its divisors is an integer number (268599630).

Almost surely, 2^1115721531 is an apocalyptic number.

1115721531 is a deficient number, since it is larger than the sum of its proper divisors (495876249).

1115721531 is a wasteful number, since it uses less digits than its factorization.

1115721531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123969065 (or 123969062 counting only the distinct ones).

The product of its digits is 1050, while the sum is 27.

The square root of 1115721531 is about 33402.4180412137. The cubic root of 1115721531 is about 1037.1747564434.

Adding to 1115721531 its reverse (1351275111), we get a palindrome (2466996642).

The spelling of 1115721531 in words is "one billion, one hundred fifteen million, seven hundred twenty-one thousand, five hundred thirty-one".