261533602612015 has 4 divisors (see below), whose sum is σ = 313840323134424. Its totient is φ = 209226882089608.

The previous prime is 261533602612013. The next prime is 261533602612067. The reversal of 261533602612015 is 510216206335162.

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 261533602612015 - 2¹ = 261533602612013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261533602612013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26153360261197 + ... + 26153360261206.

It is an arithmetic number, because the mean of its divisors is an integer number (78460080783606).

Almost surely, 2^{261533602612015} is an apocalyptic number.

261533602612015 is a deficient number, since it is larger than the sum of its proper divisors (52306720522409).

261533602612015 is an equidigital number, since it uses as much as digits as its factorization.

261533602612015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52306720522408.

The product of its (nonzero) digits is 388800, while the sum is 43.

Adding to 261533602612015 its reverse (510216206335162), we get a palindrome (771749808947177).

The spelling of 261533602612015 in words is "two hundred sixty-one trillion, five hundred thirty-three billion, six hundred two million, six hundred twelve thousand, fifteen".