261988018015 has 24 divisors (see below), whose sum is σ = 324184124880. Its totient is φ = 203242443264.

The previous prime is 261988017989. The next prime is 261988018031. The reversal of 261988018015 is 510810889162.

It is not a de Polignac number, because 261988018015 - 2⁷ = 261988017887 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261988018015.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1183119 + ... + 1386991.

It is an arithmetic number, because the mean of its divisors is an integer number (13507671870).

Almost surely, 2^261988018015 is an apocalyptic number.

261988018015 is a deficient number, since it is larger than the sum of its proper divisors (62196106865).

261988018015 is a wasteful number, since it uses less digits than its factorization.

261988018015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204103 (or 204060 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 49.

The spelling of 261988018015 in words is "two hundred sixty-one billion, nine hundred eighty-eight million, eighteen thousand, fifteen".