66155515506 has 32 divisors (see below), whose sum is σ = 147654259200. Its totient is φ = 21955538160.

The previous prime is 66155515493. The next prime is 66155515571. The reversal of 66155515506 is 60551555166.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2662530 + ... + 2687261.

It is an arithmetic number, because the mean of its divisors is an integer number (4614195600).

Almost surely, 2^66155515506 is an apocalyptic number.

66155515506 is an abundant number, since it is smaller than the sum of its proper divisors (81498743694).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66155515506 is a wasteful number, since it uses less digits than its factorization.

66155515506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5350031 (or 5350025 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 66155515506 in words is "sixty-six billion, one hundred fifty-five million, five hundred fifteen thousand, five hundred six".