261812544000 has 640 divisors, whose sum is σ = 1007227533312. Its totient is φ = 59096678400.

The previous prime is 261812543999. The next prime is 261812544023. The reversal of 261812544000 is 445218162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 111550827 + ... + 111553173.

Almost surely, 2^261812544000 is an apocalyptic number.

261812544000 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 261812544000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (503613766656).

261812544000 is an abundant number, since it is smaller than the sum of its proper divisors (745414989312).

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

261812544000 is an equidigital number, since it uses as much as digits as its factorization.

261812544000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2473 (or 2447 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The spelling of 261812544000 in words is "two hundred sixty-one billion, eight hundred twelve million, five hundred forty-four thousand".