78666225 has 96 divisors (see below), whose sum is σ = 154275840. Its totient is φ = 34944000.

The previous prime is 78666209. The next prime is 78666227. The reversal of 78666225 is 52266687.

It is not a de Polignac number, because 78666225 - 2⁴ = 78666209 is a prime.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78666227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 995736 + ... + 995814.

It is an arithmetic number, because the mean of its divisors is an integer number (1607040).

Almost surely, 2^78666225 is an apocalyptic number.

78666225 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

78666225 is the 7242-nd pentagonal number.

It is an amenable number.

78666225 is a deficient number, since it is larger than the sum of its proper divisors (75609615).

78666225 is a wasteful number, since it uses less digits than its factorization.

78666225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 186 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 78666225 is about 8869.3982321238. The cubic root of 78666225 is about 428.4788962928.

It can be divided in two parts, 786662 and 25, that added together give a palindrome (786687).

The spelling of 78666225 in words is "seventy-eight million, six hundred sixty-six thousand, two hundred twenty-five".