261216730 has 32 divisors (see below), whose sum is σ = 498655440. Its totient is φ = 98181120.

The previous prime is 261216689. The next prime is 261216737. The reversal of 261216730 is 37612162.

It can be written as a sum of positive squares in 8 ways, for example, as 46799281 + 214417449 = 6841^2 + 14643^2 .

It is not an unprimeable number, because it can be changed into a prime (261216737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191250 + ... + 192610.

Almost surely, 2^261216730 is an apocalyptic number.

261216730 is a deficient number, since it is larger than the sum of its proper divisors (237438710).

261216730 is a wasteful number, since it uses less digits than its factorization.

261216730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2514.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 261216730 is about 16162.2006546138. The cubic root of 261216730 is about 639.2444942354.

Adding to 261216730 its reverse (37612162), we get a palindrome (298828892).

The spelling of 261216730 in words is "two hundred sixty-one million, two hundred sixteen thousand, seven hundred thirty".