66878564 has 12 divisors (see below), whose sum is σ = 118196988. Its totient is φ = 33108000.

The previous prime is 66878557. The next prime is 66878569. The reversal of 66878564 is 46587866.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 35046400 + 31832164 = 5920^2 + 5642^2 .

It is not an unprimeable number, because it can be changed into a prime (66878569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82367 + ... + 83174.

It is an arithmetic number, because the mean of its divisors is an integer number (9849749).

Almost surely, 2^66878564 is an apocalyptic number.

It is an amenable number.

66878564 is a deficient number, since it is larger than the sum of its proper divisors (51318424).

66878564 is a wasteful number, since it uses less digits than its factorization.

66878564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165646 (or 165644 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 50.

The square root of 66878564 is about 8177.9315233132. The cubic root of 66878564 is about 405.9092794785.

It can be divided in two parts, 6687 and 8564, that added together give a palindrome (15251).

The spelling of 66878564 in words is "sixty-six million, eight hundred seventy-eight thousand, five hundred sixty-four".