66817828465 has 4 divisors (see below), whose sum is σ = 80181394164. Its totient is φ = 53454262768.

The previous prime is 66817828459. The next prime is 66817828489. The reversal of 66817828465 is 56482871866.

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

It can be written as a sum of positive squares in 2 ways, for example, as 35699457249 + 31118371216 = 188943^2 + 176404^2 .

It is a cyclic number.

It is not a de Polignac number, because 66817828465 - 2³⁵ = 32458090097 is a prime.

It is a super-3 number, since 3×66817828465³ (a number of 33 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6681782842 + ... + 6681782851.

It is an arithmetic number, because the mean of its divisors is an integer number (20045348541).

Almost surely, 2^66817828465 is an apocalyptic number.

It is an amenable number.

66817828465 is a deficient number, since it is larger than the sum of its proper divisors (13363565699).

66817828465 is a wasteful number, since it uses less digits than its factorization.

66817828465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13363565698.

The product of its digits is 30965760, while the sum is 61.

The spelling of 66817828465 in words is "sixty-six billion, eight hundred seventeen million, eight hundred twenty-eight thousand, four hundred sixty-five".