261240751656 has 24 divisors (see below), whose sum is σ = 707527035930. Its totient is φ = 87080250528.

The previous prime is 261240751621. The next prime is 261240751661. The reversal of 261240751656 is 656157042162.

261240751656 is a `hidden beast` number, since 2 + 6 + 124 + 0 + 7 + 516 + 5 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 203251295556 + 57989456100 = 450834^2 + 240810^2 .

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

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 5 ways as a sum of consecutive naturals, for example, 1814171815 + ... + 1814171958.

Almost surely, 2^261240751656 is an apocalyptic number.

It is an amenable number.

261240751656 is an abundant number, since it is smaller than the sum of its proper divisors (446286284274).

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

261240751656 is a wasteful number, since it uses less digits than its factorization.

261240751656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3628343785 (or 3628343778 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 45.

The spelling of 261240751656 in words is "two hundred sixty-one billion, two hundred forty million, seven hundred fifty-one thousand, six hundred fifty-six".