261154727089 has 3 divisors (see below), whose sum is σ = 261155238123. Its totient is φ = 261154216056.

The previous prime is 261154727083. The next prime is 261154727101. The reversal of 261154727089 is 980727451162.

The square root of 261154727089 is 511033.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 31721391025 + 229433336064 = 178105^2 + 478992^2 .

It is not a de Polignac number, because 261154727089 - 2⁹ = 261154726577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261154727083) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 255517 + ... + 766549.

It is an arithmetic number, because the mean of its divisors is an integer number (87051746041).

Almost surely, 2^261154727089 is an apocalyptic number.

261154727089 is the 511033-rd square number.

261154727089 is the 255517-th centered octagonal number.

It is an amenable number.

261154727089 is a deficient number, since it is larger than the sum of its proper divisors (511034).

261154727089 is an frugal number, since it uses more digits than its factorization.

261154727089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022066 (or 511033 counting only the distinct ones).

The product of its (nonzero) digits is 1693440, while the sum is 52.

The spelling of 261154727089 in words is "two hundred sixty-one billion, one hundred fifty-four million, seven hundred twenty-seven thousand, eighty-nine".