261204520 has 32 divisors (see below), whose sum is σ = 590020200. Its totient is φ = 104071168.

The previous prime is 261204443. The next prime is 261204523. The reversal of 261204520 is 25402162.

It can be written as a sum of positive squares in 4 ways, for example, as 225420196 + 35784324 = 15014^2 + 5982^2 .

It is a junction number, because it is equal to n+sod(n) for n = 261204491 and 261204500.

It is not an unprimeable number, because it can be changed into a prime (261204523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2425 + ... + 22984.

Almost surely, 2^261204520 is an apocalyptic number.

261204520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261204520 is an abundant number, since it is smaller than the sum of its proper divisors (328815680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261204520 is a wasteful number, since it uses less digits than its factorization.

261204520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25677 (or 25673 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 261204520 is about 16161.8229169856. The cubic root of 261204520 is about 639.2345340555.

Adding to 261204520 its reverse (25402162), we get a palindrome (286606682).

The spelling of 261204520 in words is "two hundred sixty-one million, two hundred four thousand, five hundred twenty".