72166709 has 6 divisors (see below), whose sum is σ = 75441366. Its totient is φ = 69028520.

The previous prime is 72166673. The next prime is 72166711. The reversal of 72166709 is 90766127.

It can be written as a sum of positive squares in only one way, i.e., 44182609 + 27984100 = 6647^2 + 5290^2 .

It is not a de Polignac number, because 72166709 - 2⁸ = 72166453 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72166789) 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 5 ways as a sum of consecutive naturals, for example, 67682 + ... + 68739.

It is an arithmetic number, because the mean of its divisors is an integer number (12573561).

Almost surely, 2^72166709 is an apocalyptic number.

It is an amenable number.

72166709 is a deficient number, since it is larger than the sum of its proper divisors (3274657).

72166709 is a wasteful number, since it uses less digits than its factorization.

72166709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136467 (or 136444 counting only the distinct ones).

The product of its (nonzero) digits is 31752, while the sum is 38.

The square root of 72166709 is about 8495.0991165495. The cubic root of 72166709 is about 416.3375992413.

The spelling of 72166709 in words is "seventy-two million, one hundred sixty-six thousand, seven hundred nine".