261850017068640 has 3840 divisors, whose sum is σ = 1267321691059200. Its totient is φ = 50190554050560.

The previous prime is 261850017068597. The next prime is 261850017068663. The reversal of 261850017068640 is 46860710058162.

261850017068640 is a `hidden beast` number, since 2 + 6 + 1 + 8 + 500 + 1 + 70 + 6 + 8 + 64 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 639 ways as a sum of consecutive naturals, for example, 179472252231 + ... + 179472253689.

It is an arithmetic number, because the mean of its divisors is an integer number (330031690380).

Almost surely, 2^{261850017068640} is an apocalyptic number.

261850017068640 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 261850017068640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (633660845529600).

261850017068640 is an abundant number, since it is smaller than the sum of its proper divisors (1005471673990560).

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

261850017068640 is a wasteful number, since it uses less digits than its factorization.

261850017068640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557 (or 1500 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 261850017068640 in words is "two hundred sixty-one trillion, eight hundred fifty billion, seventeen million, sixty-eight thousand, six hundred forty".