261138180 has 48 divisors (see below), whose sum is σ = 731896704. Its totient is φ = 69569280.

The previous prime is 261138161. The next prime is 261138187. The reversal of 261138180 is 81831162.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (261138187) 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, 105760 + ... + 108200.

It is an arithmetic number, because the mean of its divisors is an integer number (15247848).

Almost surely, 2^261138180 is an apocalyptic number.

261138180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261138180 is an abundant number, since it is smaller than the sum of its proper divisors (470758524).

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

261138180 is a wasteful number, since it uses less digits than its factorization.

261138180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4236 (or 4234 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 261138180 is about 16159.7704191613. The cubic root of 261138180 is about 639.1804124683.

The spelling of 261138180 in words is "two hundred sixty-one million, one hundred thirty-eight thousand, one hundred eighty".