261828661140 has 48 divisors (see below), whose sum is σ = 814578058560. Its totient is φ = 69820976160.

The previous prime is 261828661123. The next prime is 261828661243. The reversal of 261828661140 is 41166828162.

It is a happy number.

261828661140 is a `hidden beast` number, since 2 + 6 + 1 + 8 + 28 + 6 + 611 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 242433406 + ... + 242434485.

It is an arithmetic number, because the mean of its divisors is an integer number (16970376220).

Almost surely, 2^261828661140 is an apocalyptic number.

261828661140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261828661140 is an abundant number, since it is smaller than the sum of its proper divisors (552749397420).

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

261828661140 is a wasteful number, since it uses less digits than its factorization.

261828661140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484867909 (or 484867901 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 261828661140 in words is "two hundred sixty-one billion, eight hundred twenty-eight million, six hundred sixty-one thousand, one hundred forty".