66749372881 has 27 divisors (see below), whose sum is σ = 71593468681. Its totient is φ = 62227315304.

The previous prime is 66749372863. The next prime is 66749372933. The reversal of 66749372881 is 18827394766.

It is a happy number.

The square root of 66749372881 is 258359.

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

66749372881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66749372881 - 2¹¹ = 66749370833 is a prime.

It is a super-2 number, since 2×66749372881² (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 (66749372861) 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, 279285960 + ... + 279286198.

Almost surely, 2^66749372881 is an apocalyptic number.

66749372881 is the 258359-th square number.

66749372881 is the 129180-th centered octagonal number.

It is an amenable number.

66749372881 is a deficient number, since it is larger than the sum of its proper divisors (4844095800).

66749372881 is an frugal number, since it uses more digits than its factorization.

66749372881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618 (or 309 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 61.

The spelling of 66749372881 in words is "sixty-six billion, seven hundred forty-nine million, three hundred seventy-two thousand, eight hundred eighty-one".