261543742517497 has 16 divisors (see below), whose sum is σ = 302104530142272. Its totient is φ = 223780351083520.

The previous prime is 261543742517441. The next prime is 261543742517509. The reversal of 261543742517497 is 794715247345162.

It is not a de Polignac number, because 261543742517497 - 2³⁹ = 260993986703609 is a prime.

It is a super-2 number, since 2×261543742517497² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261543742517417) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 169977633 + ... + 171509425.

It is an arithmetic number, because the mean of its divisors is an integer number (18881533133892).

Almost surely, 2^{261543742517497} is an apocalyptic number.

It is an amenable number.

261543742517497 is a deficient number, since it is larger than the sum of its proper divisors (40560787624775).

261543742517497 is a wasteful number, since it uses less digits than its factorization.

261543742517497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2444888.

The product of its digits is 355622400, while the sum is 67.

The spelling of 261543742517497 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred forty-two million, five hundred seventeen thousand, four hundred ninety-seven".