261121360 has 80 divisors (see below), whose sum is σ = 649525392. Its totient is φ = 97280000.

The previous prime is 261121349. The next prime is 261121361. The reversal of 261121360 is 63121162.

It can be written as a sum of positive squares in 8 ways, for example, as 3968064 + 257153296 = 1992^2 + 16036^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261121361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136410 + ... + 138310.

Almost surely, 2^261121360 is an apocalyptic number.

261121360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

261121360 is the 8080-th decagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261121360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (324762696).

261121360 is an abundant number, since it is smaller than the sum of its proper divisors (388404032).

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

261121360 is a wasteful number, since it uses less digits than its factorization.

261121360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032 (or 2026 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 261121360 is about 16159.2499825951. The cubic root of 261121360 is about 639.1666888969.

It can be divided in two parts, 26112 and 1360, that added together give a palindrome (27472).

The spelling of 261121360 in words is "two hundred sixty-one million, one hundred twenty-one thousand, three hundred sixty".