1131581520 has 120 divisors (see below), whose sum is σ = 3807866400. Its totient is φ = 301148928.

The previous prime is 1131581501. The next prime is 1131581567. The reversal of 1131581520 is 251851311.

1131581520 is a `hidden beast` number, since 1 + 1 + 31 + 581 + 52 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 444411 + ... + 446949.

It is an arithmetic number, because the mean of its divisors is an integer number (31732220).

Almost surely, 2^1131581520 is an apocalyptic number.

1131581520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1131581520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1903933200).

1131581520 is an abundant number, since it is smaller than the sum of its proper divisors (2676284880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1131581520 is a wasteful number, since it uses less digits than its factorization.

1131581520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3177 (or 3168 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 27.

The square root of 1131581520 is about 33638.9880941743. The cubic root of 1131581520 is about 1042.0661341775.

The spelling of 1131581520 in words is "one billion, one hundred thirty-one million, five hundred eighty-one thousand, five hundred twenty".