261543736654645 has 16 divisors (see below), whose sum is σ = 324685678445568. Its totient is φ = 202042398049920.

The previous prime is 261543736654609. The next prime is 261543736654709. The reversal of 261543736654645 is 546456637345162.

It is not a de Polignac number, because 261543736654645 - 2¹³ = 261543736646453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1846076809 + ... + 1846218478.

It is an arithmetic number, because the mean of its divisors is an integer number (20292854902848).

Almost surely, 2^{261543736654645} is an apocalyptic number.

It is an amenable number.

261543736654645 is a deficient number, since it is larger than the sum of its proper divisors (63141941790923).

261543736654645 is a wasteful number, since it uses less digits than its factorization.

261543736654645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3692295780.

The product of its digits is 1306368000, while the sum is 67.

The spelling of 261543736654645 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred thirty-six million, six hundred fifty-four thousand, six hundred forty-five".