261536685534 has 48 divisors (see below), whose sum is σ = 573440824944. Its totient is φ = 86139648000.

The previous prime is 261536685533. The next prime is 261536685539. The reversal of 261536685534 is 435586635162.

261536685534 is a `hidden beast` number, since 2 + 6 + 15 + 36 + 68 + 5 + 534 = 666.

It is a super-2 number, since 2×261536685534² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261536685533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 746142 + ... + 1039134.

It is an arithmetic number, because the mean of its divisors is an integer number (11946683853).

Almost surely, 2^261536685534 is an apocalyptic number.

261536685534 is an abundant number, since it is smaller than the sum of its proper divisors (311904139410).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261536685534 is a wasteful number, since it uses less digits than its factorization.

261536685534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293593 (or 293590 counting only the distinct ones).

The product of its digits is 15552000, while the sum is 54.

The spelling of 261536685534 in words is "two hundred sixty-one billion, five hundred thirty-six million, six hundred eighty-five thousand, five hundred thirty-four".