261980000 has 60 divisors (see below), whose sum is σ = 644559300. Its totient is φ = 104784000.

The previous prime is 261979981. The next prime is 261980003. The reversal of 261980000 is 89162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261980003) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 13451 + ... + 26549.

It is an arithmetic number, because the mean of its divisors is an integer number (10742655).

Almost surely, 2^261980000 is an apocalyptic number.

261980000 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 261980000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322279650).

261980000 is an abundant number, since it is smaller than the sum of its proper divisors (382579300).

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

261980000 is an equidigital number, since it uses as much as digits as its factorization.

261980000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13129 (or 13106 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 261980000 is about 16185.7962423849. The cubic root of 261980000 is about 639.8665086166.

The spelling of 261980000 in words is "two hundred sixty-one million, nine hundred eighty thousand".