66185157609 has 6 divisors (see below), whose sum is σ = 95600783226. Its totient is φ = 44123438400.

The previous prime is 66185157601. The next prime is 66185157611. The reversal of 66185157609 is 90675158166.

66185157609 is a `hidden beast` number, since 6 + 6 + 18 + 5 + 15 + 7 + 609 = 666.

It can be written as a sum of positive squares in only one way, i.e., 66179106009 + 6051600 = 257253^2 + 2460^2 .

It is not a de Polignac number, because 66185157609 - 2³ = 66185157601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66185157601) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3676953192 + ... + 3676953209.

It is an arithmetic number, because the mean of its divisors is an integer number (15933463871).

Almost surely, 2^66185157609 is an apocalyptic number.

It is an amenable number.

66185157609 is a deficient number, since it is larger than the sum of its proper divisors (29415625617).

66185157609 is a wasteful number, since it uses less digits than its factorization.

66185157609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7353906407 (or 7353906404 counting only the distinct ones).

The product of its (nonzero) digits is 2721600, while the sum is 54.

The spelling of 66185157609 in words is "sixty-six billion, one hundred eighty-five million, one hundred fifty-seven thousand, six hundred nine".