66815855533 has 8 divisors (see below), whose sum is σ = 78223440960. Its totient is φ = 55873885920.

The previous prime is 66815855527. The next prime is 66815855593. The reversal of 66815855533 is 33555851866.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66815855533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66815855593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116403643 + ... + 116404216.

It is an arithmetic number, because the mean of its divisors is an integer number (9777930120).

Almost surely, 2^66815855533 is an apocalyptic number.

It is an amenable number.

66815855533 is a deficient number, since it is larger than the sum of its proper divisors (11407585427).

66815855533 is a wasteful number, since it uses less digits than its factorization.

66815855533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232807907.

The product of its digits is 12960000, while the sum is 55.

The spelling of 66815855533 in words is "sixty-six billion, eight hundred fifteen million, eight hundred fifty-five thousand, five hundred thirty-three".