66515903865 has 16 divisors (see below), whose sum is σ = 118250496000. Its totient is φ = 35475148656.

The previous prime is 66515903863. The next prime is 66515903869. The reversal of 66515903865 is 56830951566.

It is a happy number.

66515903865 is a `hidden beast` number, since 6 + 6 + 515 + 90 + 38 + 6 + 5 = 666.

It is not a de Polignac number, because 66515903865 - 2¹ = 66515903863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66515903863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 246355065 + ... + 246355334.

It is an arithmetic number, because the mean of its divisors is an integer number (7390656000).

Almost surely, 2^66515903865 is an apocalyptic number.

It is an amenable number.

66515903865 is a deficient number, since it is larger than the sum of its proper divisors (51734592135).

66515903865 is a wasteful number, since it uses less digits than its factorization.

66515903865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492710413 (or 492710407 counting only the distinct ones).

The product of its (nonzero) digits is 5832000, while the sum is 54.

The spelling of 66515903865 in words is "sixty-six billion, five hundred fifteen million, nine hundred three thousand, eight hundred sixty-five".