1231540543020 has 48 divisors (see below), whose sum is σ = 3532418735328. Its totient is φ = 320400791040.

The previous prime is 1231540542989. The next prime is 1231540543027. The reversal of 1231540543020 is 203450451321.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (1231540543027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 250310659 + ... + 250315578.

It is an arithmetic number, because the mean of its divisors is an integer number (73592056986).

Almost surely, 2^{1231540543020} is an apocalyptic number.

1231540543020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231540543020 is an abundant number, since it is smaller than the sum of its proper divisors (2300878192308).

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

1231540543020 is a wasteful number, since it uses less digits than its factorization.

1231540543020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500626290 (or 500626288 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 1231540543020 its reverse (203450451321), we get a palindrome (1434990994341).

The spelling of 1231540543020 in words is "one trillion, two hundred thirty-one billion, five hundred forty million, five hundred forty-three thousand, twenty".