261440712145765 has 32 divisors (see below), whose sum is σ = 321087959992800. Its totient is φ = 204294808780800.

The previous prime is 261440712145741. The next prime is 261440712145871. The reversal of 261440712145765 is 567541217044162.

It can be written as a sum of positive squares in 16 ways, for example, as 67852419358564 + 193588292787201 = 8237258^2 + 13913601^2 .

It is not a de Polignac number, because 261440712145765 - 2¹³ = 261440712137573 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 192053997 + ... + 193410493.

It is an arithmetic number, because the mean of its divisors is an integer number (10033998749775).

Almost surely, 2^{261440712145765} is an apocalyptic number.

It is an amenable number.

261440712145765 is a deficient number, since it is larger than the sum of its proper divisors (59647247847035).

261440712145765 is a wasteful number, since it uses less digits than its factorization.

261440712145765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1360953.

The product of its (nonzero) digits is 11289600, while the sum is 55.

The spelling of 261440712145765 in words is "two hundred sixty-one trillion, four hundred forty billion, seven hundred twelve million, one hundred forty-five thousand, seven hundred sixty-five".