261654641 has 2 divisors, whose sum is σ = 261654642. Its totient is φ = 261654640.

The previous prime is 261654611. The next prime is 261654689. The reversal of 261654641 is 146456162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 252174400 + 9480241 = 15880^2 + 3079^2 .

It is a cyclic number.

It is not a de Polignac number, because 261654641 - 2⁶ = 261654577 is a prime.

It is a Chen prime.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (261654611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130827320 + 130827321.

It is an arithmetic number, because the mean of its divisors is an integer number (130827321).

Almost surely, 2^261654641 is an apocalyptic number.

It is an amenable number.

261654641 is a deficient number, since it is larger than the sum of its proper divisors (1).

261654641 is an equidigital number, since it uses as much as digits as its factorization.

261654641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 35.

The square root of 261654641 is about 16175.7423631807. The cubic root of 261654641 is about 639.6015105624.

The spelling of 261654641 in words is "two hundred sixty-one million, six hundred fifty-four thousand, six hundred forty-one".