66512511657 has 12 divisors (see below), whose sum is σ = 96283860660. Its totient is φ = 44244643968.

The previous prime is 66512511643. The next prime is 66512511677. The reversal of 66512511657 is 75611521566.

It is a happy number.

66512511657 is a `hidden beast` number, since 6 + 65 + 12 + 511 + 65 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 60356696976 + 6155814681 = 245676^2 + 78459^2 .

It is not a de Polignac number, because 66512511657 - 2⁴ = 66512511641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66512511677) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8081532 + ... + 8089757.

It is an arithmetic number, because the mean of its divisors is an integer number (8023655055).

Almost surely, 2^66512511657 is an apocalyptic number.

It is an amenable number.

66512511657 is a deficient number, since it is larger than the sum of its proper divisors (29771349003).

66512511657 is a wasteful number, since it uses less digits than its factorization.

66512511657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16171752 (or 16171749 counting only the distinct ones).

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

Subtracting 66512511657 from its reverse (75611521566), we obtain a palindrome (9099009909).

The spelling of 66512511657 in words is "sixty-six billion, five hundred twelve million, five hundred eleven thousand, six hundred fifty-seven".