261489766104 has 256 divisors, whose sum is σ = 836165836800. Its totient is φ = 74169851904.

The previous prime is 261489766061. The next prime is 261489766117. The reversal of 261489766104 is 401667984162.

261489766104 is a `hidden beast` number, since 2 + 6 + 14 + 8 + 9 + 7 + 6 + 610 + 4 = 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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 154088584 + ... + 154090280.

It is an arithmetic number, because the mean of its divisors is an integer number (3266272800).

Almost surely, 2^261489766104 is an apocalyptic number.

261489766104 is a gapful number since it is divisible by the number (24) 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 261489766104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (418082918400).

261489766104 is an abundant number, since it is smaller than the sum of its proper divisors (574676070696).

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

261489766104 is a wasteful number, since it uses less digits than its factorization.

261489766104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2399 (or 2389 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The spelling of 261489766104 in words is "two hundred sixty-one billion, four hundred eighty-nine million, seven hundred sixty-six thousand, one hundred four".