1131205520 has 40 divisors (see below), whose sum is σ = 2643440184. Its totient is φ = 450179072.

The previous prime is 1131205511. The next prime is 1131205547. The reversal of 1131205520 is 255021311.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 510398464 + 620807056 = 22592^2 + 24916^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1131205492 and 1131205501.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20129 + ... + 51648.

Almost surely, 2^1131205520 is an apocalyptic number.

1131205520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1131205520 is an abundant number, since it is smaller than the sum of its proper divisors (1512234664).

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

1131205520 is a wasteful number, since it uses less digits than its factorization.

1131205520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71987 (or 71981 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 1131205520 is about 33633.3988767118. The cubic root of 1131205520 is about 1041.9507027320.

Adding to 1131205520 its reverse (255021311), we get a palindrome (1386226831).

The spelling of 1131205520 in words is "one billion, one hundred thirty-one million, two hundred five thousand, five hundred twenty".