66389761 has 8 divisors (see below), whose sum is σ = 67815144. Its totient is φ = 64970880.

The previous prime is 66389759. The next prime is 66389773. The reversal of 66389761 is 16798366.

It can be written as a sum of positive squares in 4 ways, for example, as 21566736 + 44823025 = 4644^2 + 6695^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66389761 - 2¹ = 66389759 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66389731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22851 + ... + 25591.

It is an arithmetic number, because the mean of its divisors is an integer number (8476893).

Almost surely, 2^66389761 is an apocalyptic number.

It is an amenable number.

66389761 is a deficient number, since it is larger than the sum of its proper divisors (1425383).

66389761 is a wasteful number, since it uses less digits than its factorization.

66389761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3251.

The product of its digits is 326592, while the sum is 46.

The square root of 66389761 is about 8147.9912248357. The cubic root of 66389761 is about 404.9179552344.

The spelling of 66389761 in words is "sixty-six million, three hundred eighty-nine thousand, seven hundred sixty-one".