66778873 has 16 divisors (see below), whose sum is σ = 82785024. Its totient is φ = 52554240.

The previous prime is 66778849. The next prime is 66778879. The reversal of 66778873 is 37887766.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 66778873 - 2⁵ = 66778841 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66778873.

It is not an unprimeable number, because it can be changed into a prime (66778879) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1965 + ... + 11722.

It is an arithmetic number, because the mean of its divisors is an integer number (5174064).

Almost surely, 2^66778873 is an apocalyptic number.

It is an amenable number.

66778873 is a deficient number, since it is larger than the sum of its proper divisors (16006151).

66778873 is a wasteful number, since it uses less digits than its factorization.

66778873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13752.

The product of its digits is 2370816, while the sum is 52.

The square root of 66778873 is about 8171.8341270488. The cubic root of 66778873 is about 405.7074927247.

The spelling of 66778873 in words is "sixty-six million, seven hundred seventy-eight thousand, eight hundred seventy-three".