261155749156 has 9 divisors (see below), whose sum is σ = 457024349649. Its totient is φ = 130577363544.

The previous prime is 261155749123. The next prime is 261155749163. The reversal of 261155749156 is 651947551162.

The square root of 261155749156 is 511034.

It is a perfect power (a square), and thus also a powerful number.

261155749156 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 188139062500 + 73016686656 = 433750^2 + 270216^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 894310 + ... + 1149826.

Almost surely, 2^261155749156 is an apocalyptic number.

261155749156 is the 511034-th square number.

It is an amenable number.

261155749156 is a deficient number, since it is larger than the sum of its proper divisors (195868600493).

261155749156 is an frugal number, since it uses more digits than its factorization.

261155749156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511038 (or 255519 counting only the distinct ones).

The product of its digits is 2268000, while the sum is 52.

The spelling of 261155749156 in words is "two hundred sixty-one billion, one hundred fifty-five million, seven hundred forty-nine thousand, one hundred fifty-six".