261244521 has 20 divisors (see below), whose sum is σ = 390890500. Its totient is φ = 173879136.

The previous prime is 261244519. The next prime is 261244537. The reversal of 261244521 is 125442162.

261244521 is a `hidden beast` number, since 2 + 612 + 4 + 45 + 2 + 1 = 666.

261244521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 108993600 + 152250921 = 10440^2 + 12339^2 .

It is not a de Polignac number, because 261244521 - 2¹ = 261244519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261244541) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 55155 + ... + 59703.

It is an arithmetic number, because the mean of its divisors is an integer number (19544525).

Almost surely, 2^261244521 is an apocalyptic number.

It is an amenable number.

261244521 is a deficient number, since it is larger than the sum of its proper divisors (129645979).

261244521 is an equidigital number, since it uses as much as digits as its factorization.

261244521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5270 (or 5261 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 261244521 is about 16163.0603847168. The cubic root of 261244521 is about 639.2671632961.

Adding to 261244521 its reverse (125442162), we get a palindrome (386686683).

The spelling of 261244521 in words is "two hundred sixty-one million, two hundred forty-four thousand, five hundred twenty-one".