66521678 has 16 divisors (see below), whose sum is σ = 102903696. Its totient is φ = 32235840.

The previous prime is 66521677. The next prime is 66521683. The reversal of 66521678 is 87612566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66521677) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5018 + ... + 12578.

It is an arithmetic number, because the mean of its divisors is an integer number (6431481).

Almost surely, 2^66521678 is an apocalyptic number.

66521678 is a deficient number, since it is larger than the sum of its proper divisors (36382018).

66521678 is a wasteful number, since it uses less digits than its factorization.

66521678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7699.

The product of its digits is 120960, while the sum is 41.

The square root of 66521678 is about 8156.0822703060. The cubic root of 66521678 is about 405.1859695640.

The spelling of 66521678 in words is "sixty-six million, five hundred twenty-one thousand, six hundred seventy-eight".