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478778161 = 218812

478778161 has 3 divisors (see below), whose sum is σ = 478800043. Its totient is φ = 478756280.

The previous prime is 478778159. The next prime is 478778213. The reversal of 478778161 is 161877874.

It is a happy number.

The square root of 478778161 is 21881.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 3538161 + 475240000 = 1881^2 + 21800^2 .

It is not a de Polignac number, because 478778161 - 21 = 478778159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (478778141) 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 2 ways as a sum of consecutive naturals, for example, 10941 + ... + 32821.

Almost surely, 2478778161 is an apocalyptic number.

478778161 is the 21881-st square number.

478778161 is the 10941-st centered octagonal number.

It is an amenable number.

478778161 is a deficient number, since it is larger than the sum of its proper divisors (21882).

478778161 is an frugal number, since it uses more digits than its factorization.

478778161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43762 (or 21881 counting only the distinct ones).

The product of its digits is 526848, while the sum is 49.

The cubic root of 478778161 is about 782.3086112376.

Multiplying 478778161 by its sum of digits (49), we get a square (23460129889 = 1531672).

The spelling of 478778161 in words is "four hundred seventy-eight million, seven hundred seventy-eight thousand, one hundred sixty-one".

Divisors: 1 21881 478778161