261144019440 has 200 divisors, whose sum is σ = 907846307808. Its totient is φ = 69572805120.

The previous prime is 261144019417. The next prime is 261144019457. The reversal of 261144019440 is 44910441162.

It is a happy number.

261144019440 is a `hidden beast` number, since 2 + 61 + 144 + 0 + 19 + 440 = 666.

261144019440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 261144019395 and 261144019404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7064205 + ... + 7101075.

Almost surely, 2^261144019440 is an apocalyptic number.

261144019440 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 261144019440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (453923153904).

261144019440 is an abundant number, since it is smaller than the sum of its proper divisors (646702288368).

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

261144019440 is a wasteful number, since it uses less digits than its factorization.

261144019440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37989 (or 37974 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 261144019440 in words is "two hundred sixty-one billion, one hundred forty-four million, nineteen thousand, four hundred forty".