1213115543 has 4 divisors (see below), whose sum is σ = 1238926560. Its totient is φ = 1187304528.

The previous prime is 1213115513. The next prime is 1213115551. The reversal of 1213115543 is 3455113121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3455113121 = 19 ⋅181848059.

It is a cyclic number.

It is not a de Polignac number, because 1213115543 - 2¹⁴ = 1213099159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213115513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12905438 + ... + 12905531.

It is an arithmetic number, because the mean of its divisors is an integer number (309731640).

Almost surely, 2^1213115543 is an apocalyptic number.

1213115543 is a deficient number, since it is larger than the sum of its proper divisors (25811017).

1213115543 is an equidigital number, since it uses as much as digits as its factorization.

1213115543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25811016.

The product of its digits is 1800, while the sum is 26.

The square root of 1213115543 is about 34829.8082538506. The cubic root of 1213115543 is about 1066.5160340784.

Adding to 1213115543 its reverse (3455113121), we get a palindrome (4668228664).

The spelling of 1213115543 in words is "one billion, two hundred thirteen million, one hundred fifteen thousand, five hundred forty-three".