261243178553 has 16 divisors (see below), whose sum is σ = 299592674304. Its totient is φ = 223151222160.

The previous prime is 261243178529. The next prime is 261243178571. The reversal of 261243178553 is 355871342162.

It is a cyclic number.

It is not a de Polignac number, because 261243178553 - 2²² = 261238984249 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261243178498 and 261243178507.

It is not an unprimeable number, because it can be changed into a prime (261243175553) 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, 17853026 + ... + 17867652.

It is an arithmetic number, because the mean of its divisors is an integer number (18724542144).

Almost surely, 2^261243178553 is an apocalyptic number.

It is an amenable number.

261243178553 is a deficient number, since it is larger than the sum of its proper divisors (38349495751).

261243178553 is a wasteful number, since it uses less digits than its factorization.

261243178553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23252.

The product of its digits is 1209600, while the sum is 47.

The spelling of 261243178553 in words is "two hundred sixty-one billion, two hundred forty-three million, one hundred seventy-eight thousand, five hundred fifty-three".