1866506374543 has 4 divisors (see below), whose sum is σ = 1866509373960. Its totient is φ = 1866503375128.

The previous prime is 1866506374511. The next prime is 1866506374559. The reversal of 1866506374543 is 3454736056681.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1866506374543 - 2⁵ = 1866506374511 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866506377543) 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, 177988 + ... + 1940281.

It is an arithmetic number, because the mean of its divisors is an integer number (466627343490).

Almost surely, 2^{1866506374543} is an apocalyptic number.

1866506374543 is a deficient number, since it is larger than the sum of its proper divisors (2999417).

1866506374543 is an equidigital number, since it uses as much as digits as its factorization.

1866506374543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2999416.

The product of its (nonzero) digits is 43545600, while the sum is 58.

The spelling of 1866506374543 in words is "one trillion, eight hundred sixty-six billion, five hundred six million, three hundred seventy-four thousand, five hundred forty-three".