66506220544 has 33 divisors (see below), whose sum is σ = 132963992427. Its totient is φ = 33248984064.

The previous prime is 66506220433. The next prime is 66506220553. The reversal of 66506220544 is 44502260566.

The square root of 66506220544 is 257888.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66506220497 and 66506220506.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 8248387 + ... + 8256445.

Almost surely, 2^66506220544 is an apocalyptic number.

66506220544 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

66506220544 is the 257888-th square number.

It is an amenable number.

66506220544 is a deficient number, since it is larger than the sum of its proper divisors (66457771883).

66506220544 is an frugal number, since it uses more digits than its factorization.

66506220544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16138 (or 8061 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 40.

The spelling of 66506220544 in words is "sixty-six billion, five hundred six million, two hundred twenty thousand, five hundred forty-four".