261188980 has 48 divisors (see below), whose sum is σ = 592739280. Its totient is φ = 96104448.

The previous prime is 261188971. The next prime is 261189001. The reversal of 261188980 is 89881162.

It can be written as a sum of positive squares in 8 ways, for example, as 32695524 + 228493456 = 5718^2 + 15116^2 .

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

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, 80836 + ... + 84004.

It is an arithmetic number, because the mean of its divisors is an integer number (12348735).

Almost surely, 2^261188980 is an apocalyptic number.

261188980 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 261188980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (296369640).

261188980 is an abundant number, since it is smaller than the sum of its proper divisors (331550300).

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

261188980 is a wasteful number, since it uses less digits than its factorization.

261188980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3508 (or 3506 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 43.

The square root of 261188980 is about 16161.3421472352. The cubic root of 261188980 is about 639.2218570139.

The spelling of 261188980 in words is "two hundred sixty-one million, one hundred eighty-eight thousand, nine hundred eighty".