261545513364131 has 4 divisors (see below), whose sum is σ = 261566184009312. Its totient is φ = 261524842718952.

The previous prime is 261545513364127. The next prime is 261545513364209. The reversal of 261545513364131 is 131463315545162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261545513364131 - 2² = 261545513364127 is a prime.

It is a super-2 number, since 2×261545513364131² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261545513364131.

It is not an unprimeable number, because it can be changed into a prime (261545513364431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10335303611 + ... + 10335328916.

It is an arithmetic number, because the mean of its divisors is an integer number (65391546002328).

Almost surely, 2^{261545513364131} is an apocalyptic number.

261545513364131 is a deficient number, since it is larger than the sum of its proper divisors (20670645181).

261545513364131 is a wasteful number, since it uses less digits than its factorization.

261545513364131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20670645180.

The product of its digits is 3888000, while the sum is 50.

The spelling of 261545513364131 in words is "two hundred sixty-one trillion, five hundred forty-five billion, five hundred thirteen million, three hundred sixty-four thousand, one hundred thirty-one".