66978875 has 16 divisors (see below), whose sum is σ = 87227712. Its totient is φ = 51251200.

The previous prime is 66978851. The next prime is 66978881. The reversal of 66978875 is 57887966.

It is a happy number.

It is not a de Polignac number, because 66978875 - 2⁶ = 66978811 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66978875.

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, 8774 + ... + 14523.

It is an arithmetic number, because the mean of its divisors is an integer number (5451732).

Almost surely, 2^66978875 is an apocalyptic number.

66978875 is a deficient number, since it is larger than the sum of its proper divisors (20248837).

66978875 is a wasteful number, since it uses less digits than its factorization.

66978875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23335 (or 23325 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 56.

The square root of 66978875 is about 8184.0622553839. The cubic root of 66978875 is about 406.1121188890.

Subtracting from 66978875 its reverse (57887966), we obtain a palindrome (9090909).

The spelling of 66978875 in words is "sixty-six million, nine hundred seventy-eight thousand, eight hundred seventy-five".