66566645 has 8 divisors (see below), whose sum is σ = 84578904. Its totient is φ = 50120704.

The previous prime is 66566639. The next prime is 66566651. The reversal of 66566645 is 54666566.

It is an interprime number because it is at equal distance from previous prime (66566639) and next prime (66566651).

It can be written as a sum of positive squares in 4 ways, for example, as 35307364 + 31259281 = 5942^2 + 5591^2 .

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 66566645 - 2¹⁰ = 66565621 is a prime.

It is a super-2 number, since 2×66566645² = 8862236453112050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66566596 and 66566605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391484 + ... + 391653.

It is an arithmetic number, because the mean of its divisors is an integer number (10572363).

Almost surely, 2^66566645 is an apocalyptic number.

It is an amenable number.

66566645 is a deficient number, since it is larger than the sum of its proper divisors (18012259).

66566645 is a wasteful number, since it uses less digits than its factorization.

66566645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783159.

The product of its digits is 777600, while the sum is 44.

The square root of 66566645 is about 8158.8384589965. The cubic root of 66566645 is about 405.2772475461.

The spelling of 66566645 in words is "sixty-six million, five hundred sixty-six thousand, six hundred forty-five".