66388945 has 16 divisors (see below), whose sum is σ = 95840640. Its totient is φ = 43127424.

The previous prime is 66388937. The next prime is 66388951. The reversal of 66388945 is 54988366.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 66388945 - 2³ = 66388937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49252 + ... + 50581.

It is an arithmetic number, because the mean of its divisors is an integer number (5990040).

Almost surely, 2^66388945 is an apocalyptic number.

It is an amenable number.

66388945 is a deficient number, since it is larger than the sum of its proper divisors (29451695).

66388945 is a wasteful number, since it uses less digits than its factorization.

66388945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99864.

The product of its digits is 1244160, while the sum is 49.

The square root of 66388945 is about 8147.9411509902. The cubic root of 66388945 is about 404.9162962717.

The spelling of 66388945 in words is "sixty-six million, three hundred eighty-eight thousand, nine hundred forty-five".