66680945 has 8 divisors (see below), whose sum is σ = 80064936. Its totient is φ = 53312896.

The previous prime is 66680909. The next prime is 66680951. The reversal of 66680945 is 54908666.

It can be written as a sum of positive squares in 4 ways, for example, as 5340721 + 61340224 = 2311^2 + 7832^2 .

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 66680945 - 2⁸ = 66680689 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66680896 and 66680905.

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, 9179 + ... + 14751.

It is an arithmetic number, because the mean of its divisors is an integer number (10008117).

Almost surely, 2^66680945 is an apocalyptic number.

It is an amenable number.

66680945 is a deficient number, since it is larger than the sum of its proper divisors (13383991).

66680945 is a wasteful number, since it uses less digits than its factorization.

66680945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7971.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 66680945 is about 8165.8401282416. The cubic root of 66680945 is about 405.5090788743.

The spelling of 66680945 in words is "sixty-six million, six hundred eighty thousand, nine hundred forty-five".