66878405 has 16 divisors (see below), whose sum is σ = 87709824. Its totient is φ = 48550080.

The previous prime is 66878401. The next prime is 66878407. The reversal of 66878405 is 50487866.

It is not a de Polignac number, because 66878405 - 2² = 66878401 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66878401) 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, 53447 + ... + 54683.

It is an arithmetic number, because the mean of its divisors is an integer number (5481864).

Almost surely, 2^66878405 is an apocalyptic number.

It is an amenable number.

66878405 is a deficient number, since it is larger than the sum of its proper divisors (20831419).

66878405 is a wasteful number, since it uses less digits than its factorization.

66878405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2236.

The product of its (nonzero) digits is 322560, while the sum is 44.

The square root of 66878405 is about 8177.9218020228. The cubic root of 66878405 is about 405.9089578028.

The spelling of 66878405 in words is "sixty-six million, eight hundred seventy-eight thousand, four hundred five".