261278228 has 12 divisors (see below), whose sum is σ = 457372692. Its totient is φ = 130600320.

The previous prime is 261278221. The next prime is 261278233. The reversal of 261278228 is 822872162.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 81396484 + 179881744 = 9022^2 + 13412^2 .

It is a junction number, because it is equal to n+sod(n) for n = 261278191 and 261278200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261278221) 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 3 ways as a sum of consecutive naturals, for example, 9818 + ... + 24878.

It is an arithmetic number, because the mean of its divisors is an integer number (38114391).

Almost surely, 2^261278228 is an apocalyptic number.

It is an amenable number.

261278228 is a deficient number, since it is larger than the sum of its proper divisors (196094464).

261278228 is a wasteful number, since it uses less digits than its factorization.

261278228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19402 (or 19400 counting only the distinct ones).

The product of its digits is 43008, while the sum is 38.

The square root of 261278228 is about 16164.1030682188. The cubic root of 261278228 is about 639.2946558684.

The spelling of 261278228 in words is "two hundred sixty-one million, two hundred seventy-eight thousand, two hundred twenty-eight".