66515761215 has 48 divisors (see below), whose sum is σ = 118221629760. Its totient is φ = 34584560640.

The previous prime is 66515761211. The next prime is 66515761217. The reversal of 66515761215 is 51216751566.

It is a happy number.

66515761215 is a `hidden beast` number, since 6 + 6 + 5 + 15 + 7 + 612 + 15 = 666.

It is not a de Polignac number, because 66515761215 - 2² = 66515761211 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66515761211) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 202966 + ... + 417404.

It is an arithmetic number, because the mean of its divisors is an integer number (2462950620).

Almost surely, 2^66515761215 is an apocalyptic number.

66515761215 is a deficient number, since it is larger than the sum of its proper divisors (51705868545).

66515761215 is a wasteful number, since it uses less digits than its factorization.

66515761215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214624 (or 214621 counting only the distinct ones).

The product of its digits is 378000, while the sum is 45.

The spelling of 66515761215 in words is "sixty-six billion, five hundred fifteen million, seven hundred sixty-one thousand, two hundred fifteen".