66881605 has 8 divisors (see below), whose sum is σ = 91723392. Its totient is φ = 45861648.

The previous prime is 66881603. The next prime is 66881623. The reversal of 66881605 is 50618866.

It is a happy number.

66881605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66881605 - 2¹ = 66881603 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66881603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 955417 + ... + 955486.

It is an arithmetic number, because the mean of its divisors is an integer number (11465424).

Almost surely, 2^66881605 is an apocalyptic number.

It is an amenable number.

66881605 is a deficient number, since it is larger than the sum of its proper divisors (24841787).

66881605 is a wasteful number, since it uses less digits than its factorization.

66881605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910915.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 66881605 is about 8178.1174484107. The cubic root of 66881605 is about 405.9154316810.

The spelling of 66881605 in words is "sixty-six million, eight hundred eighty-one thousand, six hundred five".