1231543435542 has 16 divisors (see below), whose sum is σ = 2814956424192. Its totient is φ = 351869553000.

The previous prime is 1231543435513. The next prime is 1231543435543. The reversal of 1231543435542 is 2455343451321.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 29322462751 = 1231543435542 / (1 + 2 + 3 + 1 + 5 + 4 + 3 + 4 + 3 + 5 + 5 + 4 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 1231543435494 and 1231543435503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231543435543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14661231334 + ... + 14661231417.

It is an arithmetic number, because the mean of its divisors is an integer number (175934776512).

Almost surely, 2^{1231543435542} is an apocalyptic number.

1231543435542 is an abundant number, since it is smaller than the sum of its proper divisors (1583412988650).

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

1231543435542 is a wasteful number, since it uses less digits than its factorization.

1231543435542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29322462763.

The product of its digits is 864000, while the sum is 42.

Adding to 1231543435542 its reverse (2455343451321), we get a palindrome (3686886886863).

The spelling of 1231543435542 in words is "one trillion, two hundred thirty-one billion, five hundred forty-three million, four hundred thirty-five thousand, five hundred forty-two".