66279987601 has 9 divisors (see below), whose sum is σ = 66968995153. Its totient is φ = 65598005200.

The previous prime is 66279987589. The next prime is 66279987643. The reversal of 66279987601 is 10678997266.

The square root of 66279987601 is 257449.

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 52280365201 + 13999622400 = 228649^2 + 118320^2 .

It is not a de Polignac number, because 66279987601 - 2¹¹ = 66279985553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66279987601.

It is not an unprimeable number, because it can be changed into a prime (66279987691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 26001075 + ... + 26003623.

Almost surely, 2^66279987601 is an apocalyptic number.

66279987601 is the 257449-th square number.

66279987601 is the 128725-th centered octagonal number.

It is an amenable number.

66279987601 is a deficient number, since it is larger than the sum of its proper divisors (689007552).

66279987601 is an frugal number, since it uses more digits than its factorization.

66279987601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5300 (or 2650 counting only the distinct ones).

The product of its (nonzero) digits is 13716864, while the sum is 61.

The spelling of 66279987601 in words is "sixty-six billion, two hundred seventy-nine million, nine hundred eighty-seven thousand, six hundred one".