261684149 has 2 divisors, whose sum is σ = 261684150. Its totient is φ = 261684148.

The previous prime is 261684121. The next prime is 261684167. The reversal of 261684149 is 941486162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161544100 + 100140049 = 12710^2 + 10007^2 .

It is a cyclic number.

It is not a de Polignac number, because 261684149 - 2¹² = 261680053 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261684649) by changing a digit.

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 as a sum of consecutive naturals, namely, 130842074 + 130842075.

It is an arithmetic number, because the mean of its divisors is an integer number (130842075).

Almost surely, 2^261684149 is an apocalyptic number.

It is an amenable number.

261684149 is a deficient number, since it is larger than the sum of its proper divisors (1).

261684149 is an equidigital number, since it uses as much as digits as its factorization.

261684149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 41.

The square root of 261684149 is about 16176.6544439819. The cubic root of 261684149 is about 639.6255532622.

The spelling of 261684149 in words is "two hundred sixty-one million, six hundred eighty-four thousand, one hundred forty-nine".