261731800 has 96 divisors (see below), whose sum is σ = 667814400. Its totient is φ = 94608000.

The previous prime is 261731797. The next prime is 261731801. The reversal of 261731800 is 8137162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261731801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 595981 + ... + 596419.

It is an arithmetic number, because the mean of its divisors is an integer number (6956400).

Almost surely, 2^261731800 is an apocalyptic number.

261731800 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 261731800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (333907200).

261731800 is an abundant number, since it is smaller than the sum of its proper divisors (406082600).

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

261731800 is a wasteful number, since it uses less digits than its factorization.

261731800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737 (or 728 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 261731800 is about 16178.1272092909. The cubic root of 261731800 is about 639.6643748053.

Adding to 261731800 its reverse (8137162), we get a palindrome (269868962).

The spelling of 261731800 in words is "two hundred sixty-one million, seven hundred thirty-one thousand, eight hundred".