66551755 has 4 divisors (see below), whose sum is σ = 79862112. Its totient is φ = 53241400.

The previous prime is 66551747. The next prime is 66551777. The reversal of 66551755 is 55715566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55715566 = 2 ⋅27857783.

It is not a de Polignac number, because 66551755 - 2³ = 66551747 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6655171 + ... + 6655180.

It is an arithmetic number, because the mean of its divisors is an integer number (19965528).

Almost surely, 2^66551755 is an apocalyptic number.

66551755 is a deficient number, since it is larger than the sum of its proper divisors (13310357).

66551755 is a wasteful number, since it uses less digits than its factorization.

66551755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13310356.

The product of its digits is 157500, while the sum is 40.

The square root of 66551755 is about 8157.9259006196. The cubic root of 66551755 is about 405.2470270645.

The spelling of 66551755 in words is "sixty-six million, five hundred fifty-one thousand, seven hundred fifty-five".