66063392387721 has 9 divisors (see below), whose sum is σ = 95424935336679. Its totient is φ = 44042245335936.

The previous prime is 66063392387689. The next prime is 66063392387743. The reversal of 66063392387721 is 12778329336066.

The square root of 66063392387721 is 8127939.

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

66063392387721 is a `hidden beast` number, since 6 + 60 + 6 + 339 + 238 + 7 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6337327934025 + 59726064453696 = 2517405^2 + 7728264^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 66063392387721 - 2⁵ = 66063392387689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66063392317721) 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, 23029161 + ... + 25738473.

Almost surely, 2^{66063392387721} is an apocalyptic number.

66063392387721 is the 8127939-th square number.

66063392387721 is the 4063970-th centered octagonal number.

It is an amenable number.

66063392387721 is a deficient number, since it is larger than the sum of its proper divisors (29361542948958).

66063392387721 is an frugal number, since it uses more digits than its factorization.

66063392387721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5418632 (or 2709316 counting only the distinct ones).

The product of its (nonzero) digits is 82301184, while the sum is 63.

The spelling of 66063392387721 in words is "sixty-six trillion, sixty-three billion, three hundred ninety-two million, three hundred eighty-seven thousand, seven hundred twenty-one".