261785839140 has 672 divisors, whose sum is σ = 1000324792320. Its totient is φ = 56188194048.

The previous prime is 261785839127. The next prime is 261785839151. The reversal of 261785839140 is 41938587162.

261785839140 is a `hidden beast` number, since 2 + 6 + 17 + 8 + 583 + 9 + 1 + 40 = 666.

It is a super-4 number, since 4×261785839140⁴ (a number of 47 digits) contains 4444 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 246270249 + ... + 246271311.

It is an arithmetic number, because the mean of its divisors is an integer number (1488578560).

It is a 1-persistent number, because it is pandigital, but 2⋅261785839140 = 523571678280 is not.

Almost surely, 2^261785839140 is an apocalyptic number.

261785839140 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 261785839140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (500162396160).

261785839140 is an abundant number, since it is smaller than the sum of its proper divisors (738538953180).

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

261785839140 is a wasteful number, since it uses less digits than its factorization.

261785839140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243 (or 1226 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 261785839140 in words is "two hundred sixty-one billion, seven hundred eighty-five million, eight hundred thirty-nine thousand, one hundred forty".