261237881268 has 960 divisors, whose sum is σ = 934979584000. Its totient is φ = 62960405760.

The previous prime is 261237881263. The next prime is 261237881269. The reversal of 261237881268 is 862188732162.

261237881268 is a `hidden beast` number, since 2 + 6 + 1 + 2 + 378 + 8 + 1 + 268 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261237881263) by changing a digit.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 850937571 + ... + 850937877.

Almost surely, 2^261237881268 is an apocalyptic number.

261237881268 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 261237881268, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (467489792000).

261237881268 is an abundant number, since it is smaller than the sum of its proper divisors (673741702732).

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

261237881268 is a wasteful number, since it uses less digits than its factorization.

261237881268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407 (or 382 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The spelling of 261237881268 in words is "two hundred sixty-one billion, two hundred thirty-seven million, eight hundred eighty-one thousand, two hundred sixty-eight".