1231513540 has 24 divisors (see below), whose sum is σ = 2592196992. Its totient is φ = 491459040.

The previous prime is 1231513523. The next prime is 1231513553. The reversal of 1231513540 is 453151321.

It is a happy number.

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, 62814 + ... + 80053.

It is an arithmetic number, because the mean of its divisors is an integer number (108008208).

Almost surely, 2^1231513540 is an apocalyptic number.

1231513540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231513540 is an abundant number, since it is smaller than the sum of its proper divisors (1360683452).

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

1231513540 is a wasteful number, since it uses less digits than its factorization.

1231513540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143307 (or 143305 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 1231513540 is about 35092.9272076297. The cubic root of 1231513540 is about 1071.8805663054.

Adding to 1231513540 its reverse (453151321), we get a palindrome (1684664861).

The spelling of 1231513540 in words is "one billion, two hundred thirty-one million, five hundred thirteen thousand, five hundred forty".