261645094252800 has 540 divisors, whose sum is σ = 968548993775440. Its totient is φ = 69690681815040.

The previous prime is 261645094252777. The next prime is 261645094252807. The reversal of 261645094252800 is 8252490546162.

261645094252800 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 4 + 509 + 4 + 2 + 52 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (540).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (261645094252807) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 445011819 + ... + 445599381.

Almost surely, 2^{261645094252800} is an apocalyptic number.

261645094252800 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 261645094252800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (484274496887720).

261645094252800 is an abundant number, since it is smaller than the sum of its proper divisors (706903899522640).

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

261645094252800 is an equidigital number, since it uses as much as digits as its factorization.

261645094252800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588460 (or 588432 counting only the distinct ones).

The product of its (nonzero) digits is 8294400, while the sum is 54.

The spelling of 261645094252800 in words is "two hundred sixty-one trillion, six hundred forty-five billion, ninety-four million, two hundred fifty-two thousand, eight hundred".