261611047800 has 72 divisors (see below), whose sum is σ = 878577108240. Its totient is φ = 69762945600.

The previous prime is 261611047781. The next prime is 261611047807. The reversal of 261611047800 is 8740116162.

It is a happy number.

261611047800 is a `hidden beast` number, since 26 + 161 + 1 + 0 + 478 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261611047807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 72667936 + ... + 72671535.

Almost surely, 2^261611047800 is an apocalyptic number.

261611047800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261611047800 is an abundant number, since it is smaller than the sum of its proper divisors (616966060440).

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

261611047800 is a wasteful number, since it uses less digits than its factorization.

261611047800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145339493 (or 145339481 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The spelling of 261611047800 in words is "two hundred sixty-one billion, six hundred eleven million, forty-seven thousand, eight hundred".