66549999999 has 16 divisors (see below), whose sum is σ = 101596989440. Its totient is φ = 37958271840.

The previous prime is 66549999973. The next prime is 66550000043. The reversal of 66549999999 is 99999994566.

It is a happy number.

It is not a de Polignac number, because 66549999999 - 2²⁰ = 66548951423 is a prime.

It is a Duffinian number.

66549999999 is a modest number, since divided by 999999 gives 66549 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66549979999) 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, 2917519 + ... + 2940240.

It is an arithmetic number, because the mean of its divisors is an integer number (6349811840).

Almost surely, 2^66549999999 is an apocalyptic number.

66549999999 is a deficient number, since it is larger than the sum of its proper divisors (35046989441).

66549999999 is a wasteful number, since it uses less digits than its factorization.

66549999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5858310.

The product of its digits is 3443737680, while the sum is 84.

The spelling of 66549999999 in words is "sixty-six billion, five hundred forty-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".