261554037772417 has 64 divisors (see below), whose sum is σ = 305933895590400. Its totient is φ = 221771940526080.

The previous prime is 261554037772393. The next prime is 261554037772421. The reversal of 261554037772417 is 714277730455162.

It is a cyclic number.

It is not a de Polignac number, because 261554037772417 - 2³⁹ = 261004281958529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261554037772477) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 407110084 + ... + 407752042.

It is an arithmetic number, because the mean of its divisors is an integer number (4780217118600).

Almost surely, 2^{261554037772417} is an apocalyptic number.

It is an amenable number.

261554037772417 is a deficient number, since it is larger than the sum of its proper divisors (44379857817983).

261554037772417 is a wasteful number, since it uses less digits than its factorization.

261554037772417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642698.

The product of its (nonzero) digits is 69148800, while the sum is 61.

The spelling of 261554037772417 in words is "two hundred sixty-one trillion, five hundred fifty-four billion, thirty-seven million, seven hundred seventy-two thousand, four hundred seventeen".