261315515 has 8 divisors (see below), whose sum is σ = 320871408. Its totient is φ = 204190560.

The previous prime is 261315499. The next prime is 261315541. The reversal of 261315515 is 515513162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261315515 - 2⁴ = 261315499 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 607496 + ... + 607925.

It is an arithmetic number, because the mean of its divisors is an integer number (40108926).

Almost surely, 2^261315515 is an apocalyptic number.

261315515 is a deficient number, since it is larger than the sum of its proper divisors (59555893).

261315515 is a wasteful number, since it uses less digits than its factorization.

261315515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1215469.

The product of its digits is 4500, while the sum is 29.

The square root of 261315515 is about 16165.2564161538. The cubic root of 261315515 is about 639.3250656556.

Adding to 261315515 its reverse (515513162), we get a palindrome (776828677).

The spelling of 261315515 in words is "two hundred sixty-one million, three hundred fifteen thousand, five hundred fifteen".