66161665 has 8 divisors (see below), whose sum is σ = 81083520. Its totient is φ = 51802992.

The previous prime is 66161633. The next prime is 66161687. The reversal of 66161665 is 56616166.

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

It is a cyclic number.

It is not a de Polignac number, because 66161665 - 2⁵ = 66161633 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140535 + ... + 141004.

It is an arithmetic number, because the mean of its divisors is an integer number (10135440).

Almost surely, 2^66161665 is an apocalyptic number.

It is an amenable number.

66161665 is a deficient number, since it is larger than the sum of its proper divisors (14921855).

66161665 is a wasteful number, since it uses less digits than its factorization.

66161665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281591.

The product of its digits is 38880, while the sum is 37.

The square root of 66161665 is about 8133.9821121023. The cubic root of 66161665 is about 404.4536961823.

It can be divided in two parts, 6616 and 1665, that added together give a square (8281 = 91²).

The spelling of 66161665 in words is "sixty-six million, one hundred sixty-one thousand, six hundred sixty-five".