261656100 has 108 divisors (see below), whose sum is σ = 823686864. Its totient is φ = 69474240.

The previous prime is 261656077. The next prime is 261656107. The reversal of 261656100 is 1656162.

It is a happy number.

261656100 is a `hidden beast` number, since 2 + 6 + 1 + 656 + 1 + 0 + 0 = 666.

It is not an unprimeable number, because it can be changed into a prime (261656107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 275827 + ... + 276773.

Almost surely, 2^261656100 is an apocalyptic number.

261656100 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 261656100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (411843432).

261656100 is an abundant number, since it is smaller than the sum of its proper divisors (562030764).

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

261656100 is a wasteful number, since it uses less digits than its factorization.

261656100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1274 (or 1264 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 261656100 is about 16175.7874615117. The cubic root of 261656100 is about 639.6026993774.

The spelling of 261656100 in words is "two hundred sixty-one million, six hundred fifty-six thousand, one hundred".