261975129984 has 320 divisors, whose sum is σ = 823801347600. Its totient is φ = 82413158400.

The previous prime is 261975129979. The next prime is 261975130013. The reversal of 261975129984 is 489921579162.

261975129984 is a `hidden beast` number, since 2 + 619 + 7 + 5 + 1 + 2 + 9 + 9 + 8 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 54564384 + ... + 54569184.

Almost surely, 2^261975129984 is an apocalyptic number.

261975129984 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 261975129984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (411900673800).

261975129984 is an abundant number, since it is smaller than the sum of its proper divisors (561826217616).

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

261975129984 is a wasteful number, since it uses less digits than its factorization.

261975129984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5123 (or 5102 counting only the distinct ones).

The product of its digits is 19595520, while the sum is 63.

The spelling of 261975129984 in words is "two hundred sixty-one billion, nine hundred seventy-five million, one hundred twenty-nine thousand, nine hundred eighty-four".