261263491200 has 576 divisors, whose sum is σ = 979243574400. Its totient is φ = 68772188160.

The previous prime is 261263491189. The next prime is 261263491219. The reversal of 261263491200 is 2194362162.

It is a happy number.

261263491200 is a `hidden beast` number, since 2 + 6 + 1 + 2 + 634 + 9 + 12 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a super-2 number, since 2×261263491200² (a number of 24 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 61428274 + ... + 61432526.

It is an arithmetic number, because the mean of its divisors is an integer number (1700075650).

Almost surely, 2^261263491200 is an apocalyptic number.

261263491200 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 261263491200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (489621787200).

261263491200 is an abundant number, since it is smaller than the sum of its proper divisors (717980083200).

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

261263491200 is an equidigital number, since it uses as much as digits as its factorization.

261263491200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4371 (or 4342 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The spelling of 261263491200 in words is "two hundred sixty-one billion, two hundred sixty-three million, four hundred ninety-one thousand, two hundred".