261261296100 has 360 divisors, whose sum is σ = 968870696640. Its totient is φ = 59656538880.

The previous prime is 261261296083. The next prime is 261261296123. The reversal of 261261296100 is 1692162162.

261261296100 is a `hidden beast` number, since 2 + 6 + 1 + 26 + 12 + 9 + 610 + 0 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 80909286 + ... + 80912514.

Almost surely, 2^261261296100 is an apocalyptic number.

261261296100 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 261261296100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (484435348320).

261261296100 is an abundant number, since it is smaller than the sum of its proper divisors (707609400540).

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

261261296100 is a wasteful number, since it uses less digits than its factorization.

261261296100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4689 (or 4673 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The spelling of 261261296100 in words is "two hundred sixty-one billion, two hundred sixty-one million, two hundred ninety-six thousand, one hundred".