66815543247 has 8 divisors (see below), whose sum is σ = 89090174640. Its totient is φ = 44542303680.

The previous prime is 66815543239. The next prime is 66815543273. The reversal of 66815543247 is 74234551866.

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

It is not a de Polignac number, because 66815543247 - 2³ = 66815543239 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 66815543247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66815543227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 230254 + ... + 432027.

It is an arithmetic number, because the mean of its divisors is an integer number (11136271830).

Almost surely, 2^66815543247 is an apocalyptic number.

66815543247 is a deficient number, since it is larger than the sum of its proper divisors (22274631393).

66815543247 is a wasteful number, since it uses less digits than its factorization.

66815543247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695913.

The product of its digits is 4838400, while the sum is 51.

The spelling of 66815543247 in words is "sixty-six billion, eight hundred fifteen million, five hundred forty-three thousand, two hundred forty-seven".