66130751281 has 27 divisors (see below), whose sum is σ = 81756780417. Its totient is φ = 53324490240.

The previous prime is 66130751233. The next prime is 66130751299. The reversal of 66130751281 is 18215703166.

It is a happy number.

The square root of 66130751281 is 257159.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 11179890225 + 54950861056 = 105735^2 + 234416^2 .

It is not a de Polignac number, because 66130751281 - 2²⁵ = 66097196849 is a prime.

It is a super-2 number, since 2×66130751281² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66130751381) 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, 30600841 + ... + 30603001.

Almost surely, 2^66130751281 is an apocalyptic number.

66130751281 is the 257159-th square number.

66130751281 is the 128580-th centered octagonal number.

It is an amenable number.

66130751281 is a deficient number, since it is larger than the sum of its proper divisors (15626029136).

66130751281 is an frugal number, since it uses more digits than its factorization.

66130751281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4370 (or 2185 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 40.

The spelling of 66130751281 in words is "sixty-six billion, one hundred thirty million, seven hundred fifty-one thousand, two hundred eighty-one".