261565254506 has 8 divisors (see below), whose sum is σ = 395947403940. Its totient is φ = 129582786528.

The previous prime is 261565254347. The next prime is 261565254521. The reversal of 261565254506 is 605452565162.

It can be written as a sum of positive squares in 2 ways, for example, as 234803239225 + 26762015281 = 484565^2 + 163591^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 599920091 + ... + 599920526.

Almost surely, 2^261565254506 is an apocalyptic number.

261565254506 is a deficient number, since it is larger than the sum of its proper divisors (134382149434).

261565254506 is a wasteful number, since it uses less digits than its factorization.

261565254506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1199840728.

The product of its (nonzero) digits is 2160000, while the sum is 47.

The spelling of 261565254506 in words is "two hundred sixty-one billion, five hundred sixty-five million, two hundred fifty-four thousand, five hundred six".