261066240 has 200 divisors, whose sum is σ = 935799480. Its totient is φ = 69562368.

The previous prime is 261066217. The next prime is 261066259. The reversal of 261066240 is 42660162.

It is a happy number.

261066240 is a `hidden beast` number, since 2 + 610 + 6 + 6 + 2 + 40 = 666.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 206731 + ... + 207989.

Almost surely, 2^261066240 is an apocalyptic number.

261066240 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 261066240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (467899740).

261066240 is an abundant number, since it is smaller than the sum of its proper divisors (674733240).

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

261066240 is an equidigital number, since it uses as much as digits as its factorization.

261066240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1294 (or 1269 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 261066240 is about 16157.5443678797. The cubic root of 261066240 is about 639.1217119212.

The spelling of 261066240 in words is "two hundred sixty-one million, sixty-six thousand, two hundred forty".