66551255577 has 6 divisors (see below), whose sum is σ = 96129591402. Its totient is φ = 44367503712.

The previous prime is 66551255543. The next prime is 66551255581. The reversal of 66551255577 is 77555215566.

66551255577 is a `hidden beast` number, since 6 + 6 + 5 + 5 + 12 + 55 + 577 = 666.

It can be written as a sum of positive squares in only one way, i.e., 66427845696 + 123409881 = 257736^2 + 11109^2 .

It is not a de Polignac number, because 66551255577 - 2⁶ = 66551255513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66551255677) 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, 3697291968 + ... + 3697291985.

It is an arithmetic number, because the mean of its divisors is an integer number (16021598567).

Almost surely, 2^66551255577 is an apocalyptic number.

It is an amenable number.

66551255577 is a deficient number, since it is larger than the sum of its proper divisors (29578335825).

66551255577 is a wasteful number, since it uses less digits than its factorization.

66551255577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7394583959 (or 7394583956 counting only the distinct ones).

The product of its digits is 11025000, while the sum is 54.

The spelling of 66551255577 in words is "sixty-six billion, five hundred fifty-one million, two hundred fifty-five thousand, five hundred seventy-seven".