1131507491 has 4 divisors (see below), whose sum is σ = 1131576984. Its totient is φ = 1131438000.

The previous prime is 1131507473. The next prime is 1131507511. The reversal of 1131507491 is 1947051311.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1947051311 = 3929 ⋅495559.

It is a cyclic number.

It is not a de Polignac number, because 1131507491 - 2¹⁸ = 1131245347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1131507401) 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, 4316 + ... + 47766.

It is an arithmetic number, because the mean of its divisors is an integer number (282894246).

Almost surely, 2^1131507491 is an apocalyptic number.

1131507491 is a deficient number, since it is larger than the sum of its proper divisors (69493).

1131507491 is an equidigital number, since it uses as much as digits as its factorization.

1131507491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69492.

The product of its (nonzero) digits is 3780, while the sum is 32.

The square root of 1131507491 is about 33637.8877309501. The cubic root of 1131507491 is about 1042.0434094055.

The spelling of 1131507491 in words is "one billion, one hundred thirty-one million, five hundred seven thousand, four hundred ninety-one".