261161189 has 4 divisors (see below), whose sum is σ = 261843456. Its totient is φ = 260478924.

The previous prime is 261161177. The next prime is 261161221. The reversal of 261161189 is 981161162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 981161162 = 2 ⋅490580581.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261161189 is a prime.

It is a super-3 number, since 3×261161189³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261169189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 340559 + ... + 341324.

It is an arithmetic number, because the mean of its divisors is an integer number (65460864).

Almost surely, 2^261161189 is an apocalyptic number.

It is an amenable number.

261161189 is a deficient number, since it is larger than the sum of its proper divisors (682267).

261161189 is an equidigital number, since it uses as much as digits as its factorization.

261161189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682266.

The product of its digits is 5184, while the sum is 35.

The square root of 261161189 is about 16160.4823257228. The cubic root of 261161189 is about 639.1991847394.

The spelling of 261161189 in words is "two hundred sixty-one million, one hundred sixty-one thousand, one hundred eighty-nine".