261543742517564 has 48 divisors (see below), whose sum is σ = 506708365990176. Its totient is φ = 117339298272000.

The previous prime is 261543742517513. The next prime is 261543742517581. The reversal of 261543742517564 is 465715247345162.

It is a junction number, because it is equal to n+sod(n) for n = 261543742517497 and 261543742517506.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62019662 + ... + 66102389.

It is an arithmetic number, because the mean of its divisors is an integer number (10556424291462).

Almost surely, 2^{261543742517564} is an apocalyptic number.

It is an amenable number.

261543742517564 is a deficient number, since it is larger than the sum of its proper divisors (245164623472612).

261543742517564 is a wasteful number, since it uses less digits than its factorization.

261543742517564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128123166 (or 128123164 counting only the distinct ones).

The product of its digits is 169344000, while the sum is 62.

The spelling of 261543742517564 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred forty-two million, five hundred seventeen thousand, five hundred sixty-four".