66515061601616 has 40 divisors (see below), whose sum is σ = 139627034262144. Its totient is φ = 30573270443520.

The previous prime is 66515061601561. The next prime is 66515061601661. The reversal of 66515061601616 is 61610616051566.

It is a super-2 number, since 2×66515061601616² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2843484440 + ... + 2843507831.

Almost surely, 2^{66515061601616} is an apocalyptic number.

It is an amenable number.

66515061601616 is an abundant number, since it is smaller than the sum of its proper divisors (73111972660528).

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

66515061601616 is a wasteful number, since it uses less digits than its factorization.

66515061601616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5686992339 (or 5686992333 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 50.

The spelling of 66515061601616 in words is "sixty-six trillion, five hundred fifteen billion, sixty-one million, six hundred one thousand, six hundred sixteen".