261098549 has 2 divisors, whose sum is σ = 261098550. Its totient is φ = 261098548.

The previous prime is 261098527. The next prime is 261098557. The reversal of 261098549 is 945890162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 244140625 + 16957924 = 15625^2 + 4118^2 .

It is a cyclic number.

It is not a de Polignac number, because 261098549 - 2¹⁶ = 261033013 is a prime.

It is a Sophie Germain 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 (261098249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130549274 + 130549275.

It is an arithmetic number, because the mean of its divisors is an integer number (130549275).

Almost surely, 2^261098549 is an apocalyptic number.

It is an amenable number.

261098549 is a deficient number, since it is larger than the sum of its proper divisors (1).

261098549 is an equidigital number, since it uses as much as digits as its factorization.

261098549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 261098549 is about 16158.5441485302. The cubic root of 261098549 is about 639.1480762794.

The spelling of 261098549 in words is "two hundred sixty-one million, ninety-eight thousand, five hundred forty-nine".