261356145563 has 4 divisors (see below), whose sum is σ = 261376420200. Its totient is φ = 261335870928.

The previous prime is 261356145529. The next prime is 261356145569. The reversal of 261356145563 is 365541653162.

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 261356145563 - 2³² = 257061178267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261356145569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10117970 + ... + 10143767.

It is an arithmetic number, because the mean of its divisors is an integer number (65344105050).

Almost surely, 2^261356145563 is an apocalyptic number.

261356145563 is a deficient number, since it is larger than the sum of its proper divisors (20274637).

261356145563 is a wasteful number, since it uses less digits than its factorization.

261356145563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20274636.

The product of its digits is 1944000, while the sum is 47.

The spelling of 261356145563 in words is "two hundred sixty-one billion, three hundred fifty-six million, one hundred forty-five thousand, five hundred sixty-three".