66928761 has 27 divisors (see below), whose sum is σ = 101391823.
Its totient is φ = 44177400.
The previous prime is 66928759. The next prime is 66928831. The reversal of 66928761 is 16782966.
The square root of 66928761 is 8181.
It is a perfect power (a square), and thus also a powerful number.
It can be written as a sum of positive squares in only one way, i.e., 64304361 + 2624400 = 8019^2 + 1620^2
It is a tau number, because it is divible by the number of its divisors (27).
It is not a de Polignac number, because 66928761 - 21 = 66928759 is a prime.
It is a Duffinian number.
It is a zygodrome in base 3.
It is not an unprimeable number, because it can be changed into a prime (66928261) by changing a digit.
It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 662611 + ... + 662711.
Almost surely, 266928761 is an apocalyptic number.
66928761 is the 8181-st square number.
66928761 is the 4091-st centered octagonal number.
It is an amenable number.
66928761 is a deficient number, since it is larger than the sum of its proper divisors (34463062).
66928761 is an frugal number, since it uses more digits than its factorization.
66928761 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 226 (or 104 counting only the distinct ones).
The product of its digits is 217728, while the sum is 45.
The cubic root of 66928761 is about 406.0108084353.
The spelling of 66928761 in words is "sixty-six million, nine hundred twenty-eight thousand, seven hundred sixty-one".