261667355043645 has 32 divisors (see below), whose sum is σ = 466246059206400. Its totient is φ = 139238027618112.

The previous prime is 261667355043631. The next prime is 261667355043683. The reversal of 261667355043645 is 546340553766162.

261667355043645 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 6 + 7 + 3 + 550 + 4 + 36 + 45 = 666.

It is not a de Polignac number, because 261667355043645 - 2¹² = 261667355039549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2207545182 + ... + 2207663711.

It is an arithmetic number, because the mean of its divisors is an integer number (14570189350200).

Almost surely, 2^{261667355043645} is an apocalyptic number.

It is an amenable number.

261667355043645 is a deficient number, since it is larger than the sum of its proper divisors (204578704162755).

261667355043645 is a wasteful number, since it uses less digits than its factorization.

261667355043645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4415209346 (or 4415209340 counting only the distinct ones).

The product of its (nonzero) digits is 326592000, while the sum is 63.

The spelling of 261667355043645 in words is "two hundred sixty-one trillion, six hundred sixty-seven billion, three hundred fifty-five million, forty-three thousand, six hundred forty-five".