261787500 has 216 divisors, whose sum is σ = 895723920. Its totient is φ = 64080000.

The previous prime is 261787499. The next prime is 261787507. The reversal of 261787500 is 5787162.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261787507) 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 71 ways as a sum of consecutive naturals, for example, 1462411 + ... + 1462589.

It is an arithmetic number, because the mean of its divisors is an integer number (4146870).

Almost surely, 2^261787500 is an apocalyptic number.

261787500 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 261787500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (447861960).

261787500 is an abundant number, since it is smaller than the sum of its proper divisors (633936420).

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

261787500 is a wasteful number, since it uses less digits than its factorization.

261787500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 261787500 is about 16179.8485777834. The cubic root of 261787500 is about 639.7097479424.

The spelling of 261787500 in words is "two hundred sixty-one million, seven hundred eighty-seven thousand, five hundred".