261432023771521 has 4 divisors (see below), whose sum is σ = 262324283238612. Its totient is φ = 260539764304432.

The previous prime is 261432023771467. The next prime is 261432023771543. The reversal of 261432023771521 is 125177320234162.

261432023771521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 137093913281521 + 124338110490000 = 11708711^2 + 11150700^2 .

It is a cyclic number.

It is not a de Polignac number, because 261432023771521 - 2¹¹ = 261432023769473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261432023771591) 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, 446129733106 + ... + 446129733691.

It is an arithmetic number, because the mean of its divisors is an integer number (65581070809653).

Almost surely, 2^{261432023771521} is an apocalyptic number.

It is an amenable number.

261432023771521 is a deficient number, since it is larger than the sum of its proper divisors (892259467091).

261432023771521 is an equidigital number, since it uses as much as digits as its factorization.

261432023771521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 892259467090.

The product of its (nonzero) digits is 846720, while the sum is 46.

The spelling of 261432023771521 in words is "two hundred sixty-one trillion, four hundred thirty-two billion, twenty-three million, seven hundred seventy-one thousand, five hundred twenty-one".