261499743648000 has 3456 divisors, whose sum is σ = 1138771104726528. Its totient is φ = 56770560000000.

The previous prime is 261499743647983. The next prime is 261499743648001. The reversal of 261499743648000 is 846347994162.

It is a happy number.

261499743648000 is a `hidden beast` number, since 2 + 6 + 1 + 499 + 7 + 4 + 3 + 64 + 80 + 0 + 0 = 666.

It is not an unprimeable number, because it can be changed into a prime (261499743648001) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 423824543692 + ... + 423824544308.

It is an arithmetic number, because the mean of its divisors is an integer number (329505527988).

Almost surely, 2^{261499743648000} is an apocalyptic number.

261499743648000 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 261499743648000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (569385552363264).

261499743648000 is an abundant number, since it is smaller than the sum of its proper divisors (877271361078528).

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

261499743648000 is a wasteful number, since it uses less digits than its factorization.

261499743648000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 970 (or 943 counting only the distinct ones).

The product of its (nonzero) digits is 62705664, while the sum is 63.

The spelling of 261499743648000 in words is "two hundred sixty-one trillion, four hundred ninety-nine billion, seven hundred forty-three million, six hundred forty-eight thousand".