66817828447 has 4 divisors (see below), whose sum is σ = 70334556280. Its totient is φ = 63301100616.

The previous prime is 66817828423. The next prime is 66817828459. The reversal of 66817828447 is 74482871866.

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 66817828447 - 2³⁵ = 32458090079 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 (66817828547) 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, 1758363888 + ... + 1758363925.

It is an arithmetic number, because the mean of its divisors is an integer number (17583639070).

Almost surely, 2^66817828447 is an apocalyptic number.

66817828447 is a deficient number, since it is larger than the sum of its proper divisors (3516727833).

66817828447 is a wasteful number, since it uses less digits than its factorization.

66817828447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3516727832.

The product of its digits is 28901376, while the sum is 61.

The spelling of 66817828447 in words is "sixty-six billion, eight hundred seventeen million, eight hundred twenty-eight thousand, four hundred forty-seven".