66947945 has 16 divisors (see below), whose sum is σ = 81661440. Its totient is φ = 52683264.

The previous prime is 66947899. The next prime is 66947953. The reversal of 66947945 is 54974966.

It is a cyclic number.

It is not a de Polignac number, because 66947945 - 2¹⁰ = 66946921 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66947893 and 66947902.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 107846 + ... + 108464.

It is an arithmetic number, because the mean of its divisors is an integer number (5103840).

Almost surely, 2^66947945 is an apocalyptic number.

It is an amenable number.

66947945 is a deficient number, since it is larger than the sum of its proper divisors (14713495).

66947945 is a wasteful number, since it uses less digits than its factorization.

66947945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944.

The product of its digits is 1632960, while the sum is 50.

The square root of 66947945 is about 8182.1723887975. The cubic root of 66947945 is about 406.0495967786.

The spelling of 66947945 in words is "sixty-six million, nine hundred forty-seven thousand, nine hundred forty-five".