66638513155 has 4 divisors (see below), whose sum is σ = 79966215792. Its totient is φ = 53310810520.

The previous prime is 66638513153. The next prime is 66638513177. The reversal of 66638513155 is 55131583666.

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

It is not a de Polignac number, because 66638513155 - 2¹ = 66638513153 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66638513099 and 66638513108.

It is not an unprimeable number, because it can be changed into a prime (66638513153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6663851311 + ... + 6663851320.

It is an arithmetic number, because the mean of its divisors is an integer number (19991553948).

Almost surely, 2^66638513155 is an apocalyptic number.

66638513155 is a deficient number, since it is larger than the sum of its proper divisors (13327702637).

66638513155 is a wasteful number, since it uses less digits than its factorization.

66638513155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13327702636.

The product of its digits is 1944000, while the sum is 49.

The spelling of 66638513155 in words is "sixty-six billion, six hundred thirty-eight million, five hundred thirteen thousand, one hundred fifty-five".