261315049 has 2 divisors, whose sum is σ = 261315050. Its totient is φ = 261315048.

The previous prime is 261315031. The next prime is 261315083. The reversal of 261315049 is 940513162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 257442025 + 3873024 = 16045^2 + 1968^2 .

It is a cyclic number.

It is not a de Polignac number, because 261315049 - 2¹⁷ = 261183977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261315049.

It is not a weakly prime, because it can be changed into another prime (261315749) 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, 130657524 + 130657525.

It is an arithmetic number, because the mean of its divisors is an integer number (130657525).

Almost surely, 2^261315049 is an apocalyptic number.

It is an amenable number.

261315049 is a deficient number, since it is larger than the sum of its proper divisors (1).

261315049 is an equidigital number, since it uses as much as digits as its factorization.

261315049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 261315049 is about 16165.2420025189. The cubic root of 261315049 is about 639.3246856225.

The spelling of 261315049 in words is "two hundred sixty-one million, three hundred fifteen thousand, forty-nine".