666765334249 has 27 divisors (see below), whose sum is σ = 781648749207. Its totient is φ = 567108635184.

The previous prime is 666765334217. The next prime is 666765334297. The reversal of 666765334249 is 942433567666.

The square root of 666765334249 is 816557.

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., 195439147225 + 471326187024 = 442085^2 + 686532^2 .

It is not a de Polignac number, because 666765334249 - 2⁵ = 666765334217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666765334649) 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, 897395772 + ... + 897396514.

Almost surely, 2^666765334249 is an apocalyptic number.

666765334249 is the 816557-th square number.

666765334249 is the 408279-th centered octagonal number.

It is an amenable number.

666765334249 is a deficient number, since it is larger than the sum of its proper divisors (114883414958).

666765334249 is an frugal number, since it uses more digits than its factorization.

666765334249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1814 (or 907 counting only the distinct ones).

The product of its digits is 117573120, while the sum is 61.

The spelling of 666765334249 in words is "six hundred sixty-six billion, seven hundred sixty-five million, three hundred thirty-four thousand, two hundred forty-nine".