261000149 has 2 divisors, whose sum is σ = 261000150. Its totient is φ = 261000148.

The previous prime is 261000139. The next prime is 261000193. The reversal of 261000149 is 941000162.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177369124 + 83631025 = 13318^2 + 9145^2 .

It is a cyclic number.

It is not a de Polignac number, because 261000149 - 2²⁴ = 244222933 is a prime.

It is a super-3 number, since 3×261000149³ (a number of 26 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261000139) by changing a digit.

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 as a sum of consecutive naturals, namely, 130500074 + 130500075.

It is an arithmetic number, because the mean of its divisors is an integer number (130500075).

Almost surely, 2^261000149 is an apocalyptic number.

It is an amenable number.

261000149 is a deficient number, since it is larger than the sum of its proper divisors (1).

261000149 is an equidigital number, since it uses as much as digits as its factorization.

261000149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 261000149 is about 16155.4990328371. The cubic root of 261000149 is about 639.0677744505.

The spelling of 261000149 in words is "two hundred sixty-one million, one hundred forty-nine", and thus it is an aban number.