261340553 has 2 divisors, whose sum is σ = 261340554. Its totient is φ = 261340552.

The previous prime is 261340549. The next prime is 261340567. The reversal of 261340553 is 355043162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 237992329 + 23348224 = 15427^2 + 4832^2 .

It is a cyclic number.

It is not a de Polignac number, because 261340553 - 2² = 261340549 is a prime.

It is not a weakly prime, because it can be changed into another prime (261340543) 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, 130670276 + 130670277.

It is an arithmetic number, because the mean of its divisors is an integer number (130670277).

Almost surely, 2^261340553 is an apocalyptic number.

It is an amenable number.

261340553 is a deficient number, since it is larger than the sum of its proper divisors (1).

261340553 is an equidigital number, since it uses as much as digits as its factorization.

261340553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 29.

The square root of 261340553 is about 16166.0308362937. The cubic root of 261340553 is about 639.3454840245.

The spelling of 261340553 in words is "two hundred sixty-one million, three hundred forty thousand, five hundred fifty-three".