261640115 has 24 divisors (see below), whose sum is σ = 365420160. Its totient is φ = 179083520.

The previous prime is 261640109. The next prime is 261640121. The reversal of 261640115 is 511046162.

It is an interprime number because it is at equal distance from previous prime (261640109) and next prime (261640121).

It is not a de Polignac number, because 261640115 - 2¹⁸ = 261377971 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 2435 + ... + 23004.

It is an arithmetic number, because the mean of its divisors is an integer number (15225840).

Almost surely, 2^261640115 is an apocalyptic number.

261640115 is a deficient number, since it is larger than the sum of its proper divisors (103780045).

261640115 is a wasteful number, since it uses less digits than its factorization.

261640115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25483 (or 25472 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 261640115 is about 16175.2933512811. The cubic root of 261640115 is about 639.5896743198.

Adding to 261640115 its reverse (511046162), we get a palindrome (772686277).

The spelling of 261640115 in words is "two hundred sixty-one million, six hundred forty thousand, one hundred fifteen".