66561050650 has 24 divisors (see below), whose sum is σ = 124263815580. Its totient is φ = 26525439360.

The previous prime is 66561050609. The next prime is 66561050651. The reversal of 66561050650 is 5605016566.

It can be written as a sum of positive squares in 6 ways, for example, as 30944679921 + 35616370729 = 175911^2 + 188723^2 .

It is not an unprimeable number, because it can be changed into a prime (66561050651) 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 11 ways as a sum of consecutive naturals, for example, 2460939 + ... + 2487838.

Almost surely, 2^66561050650 is an apocalyptic number.

66561050650 is a deficient number, since it is larger than the sum of its proper divisors (57702764930).

66561050650 is a wasteful number, since it uses less digits than its factorization.

66561050650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4949058 (or 4949053 counting only the distinct ones).

The product of its (nonzero) digits is 162000, while the sum is 40.

The spelling of 66561050650 in words is "sixty-six billion, five hundred sixty-one million, fifty thousand, six hundred fifty".