261558180 has 384 divisors, whose sum is σ = 965260800. Its totient is φ = 58226688.

The previous prime is 261558173. The next prime is 261558211. The reversal of 261558180 is 81855162.

261558180 is a `hidden beast` number, since 26 + 1 + 558 + 1 + 80 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4935034 + ... + 4935086.

It is an arithmetic number, because the mean of its divisors is an integer number (2513700).

Almost surely, 2^261558180 is an apocalyptic number.

261558180 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 261558180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (482630400).

261558180 is an abundant number, since it is smaller than the sum of its proper divisors (703702620).

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

261558180 is a wasteful number, since it uses less digits than its factorization.

261558180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140 (or 132 counting only the distinct ones).

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

The square root of 261558180 is about 16172.7604322824. The cubic root of 261558180 is about 639.5229028931.

The spelling of 261558180 in words is "two hundred sixty-one million, five hundred fifty-eight thousand, one hundred eighty".