261646064344465 has 16 divisors (see below), whose sum is σ = 324104935242240. Its totient is φ = 202563805426560.

The previous prime is 261646064344439. The next prime is 261646064344471. The reversal of 261646064344465 is 564443460646162.

It is not a de Polignac number, because 261646064344465 - 2²³ = 261646055955857 is a prime.

It is a super-2 number, since 2×261646064344465² (a number of 30 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 32863566 + ... + 40041304.

It is an arithmetic number, because the mean of its divisors is an integer number (20256558452640).

Almost surely, 2^{261646064344465} is an apocalyptic number.

It is an amenable number.

261646064344465 is a deficient number, since it is larger than the sum of its proper divisors (62458870897775).

261646064344465 is a wasteful number, since it uses less digits than its factorization.

261646064344465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7412952.

The product of its (nonzero) digits is 238878720, while the sum is 61.

The spelling of 261646064344465 in words is "two hundred sixty-one trillion, six hundred forty-six billion, sixty-four million, three hundred forty-four thousand, four hundred sixty-five".