1666860289 has 16 divisors (see below), whose sum is σ = 1770809040. Its totient is φ = 1566208000.

The previous prime is 1666860287. The next prime is 1666860361. The reversal of 1666860289 is 9820686661.

It can be written as a sum of positive squares in 8 ways, for example, as 2873025 + 1663987264 = 1695^2 + 40792^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666860289 - 2¹ = 1666860287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666860281) 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, 546609 + ... + 549649.

It is an arithmetic number, because the mean of its divisors is an integer number (110675565).

Almost surely, 2^1666860289 is an apocalyptic number.

It is an amenable number.

1666860289 is a deficient number, since it is larger than the sum of its proper divisors (103948751).

1666860289 is a wasteful number, since it uses less digits than its factorization.

1666860289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3572.

The product of its (nonzero) digits is 1492992, while the sum is 52.

The square root of 1666860289 is about 40827.2003571149. The cubic root of 1666860289 is about 1185.6770126509.

The spelling of 1666860289 in words is "one billion, six hundred sixty-six million, eight hundred sixty thousand, two hundred eighty-nine".