261158580 has 120 divisors (see below), whose sum is σ = 841599528. Its totient is φ = 67744512.

The previous prime is 261158567. The next prime is 261158581. The reversal of 261158580 is 85851162.

261158580 is a `hidden beast` number, since 2 + 61 + 15 + 8 + 580 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 167029776 + 94128804 = 12924^2 + 9702^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261158581) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 57762 + ... + 62118.

Almost surely, 2^261158580 is an apocalyptic number.

261158580 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 261158580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (420799764).

261158580 is an abundant number, since it is smaller than the sum of its proper divisors (580440948).

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

261158580 is a wasteful number, since it uses less digits than its factorization.

261158580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4415 (or 4404 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 36.

The square root of 261158580 is about 16160.4016039206. The cubic root of 261158580 is about 639.1970561993.

The spelling of 261158580 in words is "two hundred sixty-one million, one hundred fifty-eight thousand, five hundred eighty".