66726709 has 16 divisors (see below), whose sum is σ = 79257600. Its totient is φ = 54964224.

The previous prime is 66726701. The next prime is 66726713. The reversal of 66726709 is 90762766.

It is a happy number.

It is not a de Polignac number, because 66726709 - 2³ = 66726701 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 (66726701) 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, 51532 + ... + 52810.

It is an arithmetic number, because the mean of its divisors is an integer number (4953600).

Almost surely, 2^66726709 is an apocalyptic number.

It is an amenable number.

66726709 is a deficient number, since it is larger than the sum of its proper divisors (12530891).

66726709 is a wasteful number, since it uses less digits than its factorization.

66726709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1572.

The product of its (nonzero) digits is 190512, while the sum is 43.

The square root of 66726709 is about 8168.6418087709. The cubic root of 66726709 is about 405.6018263783.

The spelling of 66726709 in words is "sixty-six million, seven hundred twenty-six thousand, seven hundred nine".