261240415 has 4 divisors (see below), whose sum is σ = 313488504. Its totient is φ = 208992328.

The previous prime is 261240407. The next prime is 261240431. The reversal of 261240415 is 514042162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261240415 - 2³ = 261240407 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261240415.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 26124037 + ... + 26124046.

It is an arithmetic number, because the mean of its divisors is an integer number (78372126).

Almost surely, 2^261240415 is an apocalyptic number.

261240415 is a deficient number, since it is larger than the sum of its proper divisors (52248089).

261240415 is an equidigital number, since it uses as much as digits as its factorization.

261240415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52248088.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 261240415 is about 16162.9333661932. The cubic root of 261240415 is about 639.2638141417.

Adding to 261240415 its reverse (514042162), we get a palindrome (775282577).

The spelling of 261240415 in words is "two hundred sixty-one million, two hundred forty thousand, four hundred fifteen".