261031500 has 288 divisors, whose sum is σ = 899458560. Its totient is φ = 63504000.

The previous prime is 261031493. The next prime is 261031541. The reversal of 261031500 is 5130162.

261031500 is a `hidden beast` number, since 2 + 610 + 3 + 1 + 50 + 0 = 666.

261031500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3676465 + ... + 3676535.

It is an arithmetic number, because the mean of its divisors is an integer number (3123120).

Almost surely, 2^261031500 is an apocalyptic number.

261031500 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 261031500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (449729280).

261031500 is an abundant number, since it is smaller than the sum of its proper divisors (638427060).

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

261031500 is a wasteful number, since it uses less digits than its factorization.

261031500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 261031500 is about 16156.4692925156. The cubic root of 261031500 is about 639.0933614239.

Adding to 261031500 its reverse (5130162), we get a palindrome (266161662).

The spelling of 261031500 in words is "two hundred sixty-one million, thirty-one thousand, five hundred".