66809771 has 16 divisors (see below), whose sum is σ = 78624000. Its totient is φ = 55588128.

The previous prime is 66809749. The next prime is 66809789. The reversal of 66809771 is 17790866.

It is a cyclic number.

It is not a de Polignac number, because 66809771 - 2¹⁰ = 66808747 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66809731) 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, 33305 + ... + 35253.

It is an arithmetic number, because the mean of its divisors is an integer number (4914000).

Almost surely, 2^66809771 is an apocalyptic number.

66809771 is a deficient number, since it is larger than the sum of its proper divisors (11814229).

66809771 is a wasteful number, since it uses less digits than its factorization.

66809771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2098.

The product of its (nonzero) digits is 127008, while the sum is 44.

The square root of 66809771 is about 8173.7244264778. The cubic root of 66809771 is about 405.7700555119.

The spelling of 66809771 in words is "sixty-six million, eight hundred nine thousand, seven hundred seventy-one".