78840216225 has 27 divisors (see below), whose sum is σ = 141219131443. Its totient is φ = 42045869040.

The previous prime is 78840216181. The next prime is 78840216239. The reversal of 78840216225 is 52261204887.

The square root of 78840216225 is 280785.

It is a perfect power (a square), and thus also a powerful number.

78840216225 is a `hidden beast` number, since 7 + 8 + 8 + 402 + 16 + 225 = 666.

It can be written as a sum of positive squares in only one way, i.e., 28382477841 + 50457738384 = 168471^2 + 224628^2 .

It is not a de Polignac number, because 78840216225 - 2¹⁷ = 78840085153 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 4202416 + ... + 4221134.

Almost surely, 2^78840216225 is an apocalyptic number.

78840216225 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

78840216225 is the 280785-th square number.

78840216225 is the 140393-rd centered octagonal number.

It is an amenable number.

78840216225 is a deficient number, since it is larger than the sum of its proper divisors (62378915218).

78840216225 is an frugal number, since it uses more digits than its factorization.

78840216225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37454 (or 18727 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 78840216225 in words is "seventy-eight billion, eight hundred forty million, two hundred sixteen thousand, two hundred twenty-five".