66336638481 has 9 divisors (see below), whose sum is σ = 95820705019. Its totient is φ = 44223910536.

The previous prime is 66336638471. The next prime is 66336638483. The reversal of 66336638481 is 18483663366.

The square root of 66336638481 is 257559.

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., 66324276225 + 12362256 = 257535^2 + 3516^2 .

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

It is not a de Polignac number, because 66336638481 - 2⁷ = 66336638353 is a prime.

It is a super-2 number, since 2×66336638481² (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 (66336638483) 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, 729751 + ... + 815603.

Almost surely, 2^66336638481 is an apocalyptic number.

66336638481 is the 257559-th square number.

66336638481 is the 128780-th centered octagonal number.

It is an amenable number.

66336638481 is a deficient number, since it is larger than the sum of its proper divisors (29484066538).

66336638481 is an frugal number, since it uses more digits than its factorization.

66336638481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171712 (or 85856 counting only the distinct ones).

The product of its digits is 8957952, while the sum is 54.

The spelling of 66336638481 in words is "sixty-six billion, three hundred thirty-six million, six hundred thirty-eight thousand, four hundred eighty-one".