261863500 has 48 divisors (see below), whose sum is σ = 573693120. Its totient is φ = 104419200.

The previous prime is 261863489. The next prime is 261863509. The reversal of 261863500 is 5368162.

It is not an unprimeable number, because it can be changed into a prime (261863509) 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, 218904 + ... + 220096.

It is an arithmetic number, because the mean of its divisors is an integer number (11951940).

Almost surely, 2^261863500 is an apocalyptic number.

261863500 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 261863500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286846560).

261863500 is an abundant number, since it is smaller than the sum of its proper divisors (311829620).

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

261863500 is a wasteful number, since it uses less digits than its factorization.

261863500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1651 (or 1639 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 261863500 is about 16182.1970078231. The cubic root of 261863500 is about 639.7716470486.

The spelling of 261863500 in words is "two hundred sixty-one million, eight hundred sixty-three thousand, five hundred".