261530520 has 64 divisors (see below), whose sum is σ = 788991840. Its totient is φ = 69350400.

The previous prime is 261530509. The next prime is 261530557. The reversal of 261530520 is 25035162.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15700 + ... + 27740.

Almost surely, 2^261530520 is an apocalyptic number.

261530520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261530520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (394495920).

261530520 is an abundant number, since it is smaller than the sum of its proper divisors (527461320).

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

261530520 is a wasteful number, since it uses less digits than its factorization.

261530520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12236 (or 12232 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 261530520 is about 16171.9052680876. The cubic root of 261530520 is about 639.5003587347.

Adding to 261530520 its reverse (25035162), we get a palindrome (286565682).

The spelling of 261530520 in words is "two hundred sixty-one million, five hundred thirty thousand, five hundred twenty".