261657805248 has 224 divisors, whose sum is σ = 881901004800. Its totient is φ = 74522446848.

The previous prime is 261657805229. The next prime is 261657805261. The reversal of 261657805248 is 842508756162.

261657805248 is a `hidden beast` number, since 2 + 6 + 16 + 578 + 0 + 52 + 4 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (224).

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

It is a junction number, because it is equal to n+sod(n) for n = 261657805194 and 261657805203.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3800313 + ... + 3868551.

Almost surely, 2^261657805248 is an apocalyptic number.

261657805248 is a gapful number since it is divisible by the number (28) 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 261657805248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (440950502400).

261657805248 is an abundant number, since it is smaller than the sum of its proper divisors (620243199552).

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

261657805248 is a wasteful number, since it uses less digits than its factorization.

261657805248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68584 (or 68568 counting only the distinct ones).

The product of its (nonzero) digits is 6451200, while the sum is 54.

The spelling of 261657805248 in words is "two hundred sixty-one billion, six hundred fifty-seven million, eight hundred five thousand, two hundred forty-eight".