261535408693 has 12 divisors (see below), whose sum is σ = 283893562020. Its totient is φ = 240826974336.

The previous prime is 261535408639. The next prime is 261535408703. The reversal of 261535408693 is 396804535162.

It can be written as a sum of positive squares in 6 ways, for example, as 6633613809 + 254901794884 = 81447^2 + 504878^2 .

It is not a de Polignac number, because 261535408693 - 2⁹ = 261535408181 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261535408693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261535408613) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1822746 + ... + 1960987.

It is an arithmetic number, because the mean of its divisors is an integer number (23657796835).

Almost surely, 2^261535408693 is an apocalyptic number.

It is an amenable number.

261535408693 is a deficient number, since it is larger than the sum of its proper divisors (22358153327).

261535408693 is a wasteful number, since it uses less digits than its factorization.

261535408693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3784168 (or 3784155 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 52.

The spelling of 261535408693 in words is "two hundred sixty-one billion, five hundred thirty-five million, four hundred eight thousand, six hundred ninety-three".