66560621 has 8 divisors (see below), whose sum is σ = 67230264. Its totient is φ = 65894400.

The previous prime is 66560617. The next prime is 66560639. The reversal of 66560621 is 12606566.

It can be written as a sum of positive squares in 4 ways, for example, as 1177225 + 65383396 = 1085^2 + 8086^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66560621 - 2² = 66560617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66565621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54821 + ... + 56021.

It is an arithmetic number, because the mean of its divisors is an integer number (8403783).

Almost surely, 2^66560621 is an apocalyptic number.

It is an amenable number.

66560621 is a deficient number, since it is larger than the sum of its proper divisors (669643).

66560621 is a wasteful number, since it uses less digits than its factorization.

66560621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1711.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 66560621 is about 8158.4692804472. The cubic root of 66560621 is about 405.2650218847.

The spelling of 66560621 in words is "sixty-six million, five hundred sixty thousand, six hundred twenty-one".