66740709 has 16 divisors (see below), whose sum is σ = 101955200. Its totient is φ = 38041920.

The previous prime is 66740693. The next prime is 66740717. The reversal of 66740709 is 90704766.

It is not a de Polignac number, because 66740709 - 2⁴ = 66740693 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 (66740719) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5067 + ... + 12615.

It is an arithmetic number, because the mean of its divisors is an integer number (6372200).

Almost surely, 2^66740709 is an apocalyptic number.

It is an amenable number.

66740709 is a deficient number, since it is larger than the sum of its proper divisors (35214491).

66740709 is a wasteful number, since it uses less digits than its factorization.

66740709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7980.

The product of its (nonzero) digits is 63504, while the sum is 39.

The square root of 66740709 is about 8169.4986994307. The cubic root of 66740709 is about 405.6301909746.

The spelling of 66740709 in words is "sixty-six million, seven hundred forty thousand, seven hundred nine".