261808000 has 64 divisors (see below), whose sum is σ = 650959920. Its totient is φ = 104716800.

The previous prime is 261807991. The next prime is 261808013. The reversal of 261808000 is 808162.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7819 + ... + 24181.

Almost surely, 2^261808000 is an apocalyptic number.

261808000 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 261808000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (325479960).

261808000 is an abundant number, since it is smaller than the sum of its proper divisors (389151920).

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

261808000 is an equidigital number, since it uses as much as digits as its factorization.

261808000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16392 (or 16370 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 261808000 is about 16180.4820694564. The cubic root of 261808000 is about 639.7264455916.

The spelling of 261808000 in words is "two hundred sixty-one million, eight hundred eight thousand".