66779862724 has 9 divisors (see below), whose sum is σ = 116865664237. Its totient is φ = 33389672944.

The previous prime is 66779862703. The next prime is 66779862731. The reversal of 66779862724 is 42726897766.

The square root of 66779862724 is 258418.

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., 1407600324 + 65372262400 = 37518^2 + 255680^2 .

It is a Duffinian number.

It is an unprimeable number.

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 2 ways as a sum of consecutive naturals, for example, 452232 + ... + 581440.

Almost surely, 2^66779862724 is an apocalyptic number.

66779862724 is the 258418-th square number.

It is an amenable number.

66779862724 is a deficient number, since it is larger than the sum of its proper divisors (50085801513).

66779862724 is an frugal number, since it uses more digits than its factorization.

66779862724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258422 (or 129211 counting only the distinct ones).

The product of its digits is 85349376, while the sum is 64.

Multiplying 66779862724 by its sum of digits (64), we get a square (4273911214336 = 2067344²).

The spelling of 66779862724 in words is "sixty-six billion, seven hundred seventy-nine million, eight hundred sixty-two thousand, seven hundred twenty-four".