66438191543 has 2 divisors, whose sum is σ = 66438191544. Its totient is φ = 66438191542.

The previous prime is 66438191531. The next prime is 66438191579. The reversal of 66438191543 is 34519183466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66438191543 - 2²⁴ = 66421414327 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66438191491 and 66438191500.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66438191243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33219095771 + 33219095772.

It is an arithmetic number, because the mean of its divisors is an integer number (33219095772).

Almost surely, 2^66438191543 is an apocalyptic number.

66438191543 is a deficient number, since it is larger than the sum of its proper divisors (1).

66438191543 is an equidigital number, since it uses as much as digits as its factorization.

66438191543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1866240, while the sum is 50.

The spelling of 66438191543 in words is "sixty-six billion, four hundred thirty-eight million, one hundred ninety-one thousand, five hundred forty-three".