261550579 has 2 divisors, whose sum is σ = 261550580. Its totient is φ = 261550578.

The previous prime is 261550571. The next prime is 261550589. The reversal of 261550579 is 975055162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261550579 - 2³ = 261550571 is a prime.

It is not a weakly prime, because it can be changed into another prime (261550571) 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, 130775289 + 130775290.

It is an arithmetic number, because the mean of its divisors is an integer number (130775290).

Almost surely, 2^261550579 is an apocalyptic number.

261550579 is a deficient number, since it is larger than the sum of its proper divisors (1).

261550579 is an equidigital number, since it uses as much as digits as its factorization.

261550579 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 94500, while the sum is 40.

The square root of 261550579 is about 16172.5254366781. The cubic root of 261550579 is about 639.5167078907.

The spelling of 261550579 in words is "two hundred sixty-one million, five hundred fifty thousand, five hundred seventy-nine".