261156808728 has 24 divisors (see below), whose sum is σ = 707299690500. Its totient is φ = 87052269552.

The previous prime is 261156808687. The next prime is 261156808729. The reversal of 261156808728 is 827808651162.

261156808728 is a `hidden beast` number, since 2 + 6 + 1 + 1 + 568 + 0 + 8 + 72 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261156808729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1813588878 + ... + 1813589021.

Almost surely, 2^261156808728 is an apocalyptic number.

It is an amenable number.

261156808728 is an abundant number, since it is smaller than the sum of its proper divisors (446142881772).

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

261156808728 is a wasteful number, since it uses less digits than its factorization.

261156808728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3627177911 (or 3627177904 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 54.

The spelling of 261156808728 in words is "two hundred sixty-one billion, one hundred fifty-six million, eight hundred eight thousand, seven hundred twenty-eight".