1531121440 has 24 divisors (see below), whose sum is σ = 3617274780. Its totient is φ = 612448512.

The previous prime is 1531121407. The next prime is 1531121443. The reversal of 1531121440 is 441211351.

It can be written as a sum of positive squares in 2 ways, for example, as 1521312016 + 9809424 = 39004^2 + 3132^2 .

It is not an unprimeable number, because it can be changed into a prime (1531121443) 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 3 ways as a sum of consecutive naturals, for example, 4784595 + ... + 4784914.

Almost surely, 2^1531121440 is an apocalyptic number.

1531121440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1531121440 is an abundant number, since it is smaller than the sum of its proper divisors (2086153340).

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

1531121440 is an equidigital number, since it uses as much as digits as its factorization.

1531121440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9569524 (or 9569516 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 1531121440 is about 39129.5468923421. The cubic root of 1531121440 is about 1152.5768153668.

Adding to 1531121440 its reverse (441211351), we get a palindrome (1972332791).

The spelling of 1531121440 in words is "one billion, five hundred thirty-one million, one hundred twenty-one thousand, four hundred forty".