261533524721101 has 4 divisors (see below), whose sum is σ = 261542620618972. Its totient is φ = 261524428823232.

The previous prime is 261533524721087. The next prime is 261533524721113. The reversal of 261533524721101 is 101127425335162.

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

It can be written as a sum of positive squares in 2 ways, for example, as 188759846220100 + 72773678501001 = 13738990^2 + 8530749^2 .

It is a cyclic number.

It is not a de Polignac number, because 261533524721101 - 2²⁷ = 261533390503373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261533524701101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4547905806 + ... + 4547963311.

It is an arithmetic number, because the mean of its divisors is an integer number (65385655154743).

Almost surely, 2^{261533524721101} is an apocalyptic number.

It is an amenable number.

261533524721101 is a deficient number, since it is larger than the sum of its proper divisors (9095897871).

261533524721101 is an equidigital number, since it uses as much as digits as its factorization.

261533524721101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9095897870.

The product of its (nonzero) digits is 302400, while the sum is 43.

The spelling of 261533524721101 in words is "two hundred sixty-one trillion, five hundred thirty-three billion, five hundred twenty-four million, seven hundred twenty-one thousand, one hundred one".