261416441521 has 3 divisors (see below), whose sum is σ = 261416952811. Its totient is φ = 261415930232.

The previous prime is 261416441467. The next prime is 261416441527. The reversal of 261416441521 is 125144614162.

The square root of 261416441521 is 511289.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 261285567921 + 130873600 = 511161^2 + 11440^2 .

It is not a de Polignac number, because 261416441521 - 2²⁵ = 261382887089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261416441527) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 255645 + ... + 766933.

Almost surely, 2^261416441521 is an apocalyptic number.

261416441521 is the 511289-th square number.

261416441521 is the 255645-th centered octagonal number.

It is an amenable number.

261416441521 is a deficient number, since it is larger than the sum of its proper divisors (511290).

261416441521 is an frugal number, since it uses more digits than its factorization.

261416441521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1022578 (or 511289 counting only the distinct ones).

The product of its digits is 46080, while the sum is 37.

The spelling of 261416441521 in words is "two hundred sixty-one billion, four hundred sixteen million, four hundred forty-one thousand, five hundred twenty-one".