261153553 has 2 divisors, whose sum is σ = 261153554. Its totient is φ = 261153552.

The previous prime is 261153551. The next prime is 261153583. The reversal of 261153553 is 355351162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161493264 + 99660289 = 12708^2 + 9983^2 .

It is a cyclic number.

It is not a de Polignac number, because 261153553 - 2¹ = 261153551 is a prime.

Together with 261153551, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (261153551) 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, 130576776 + 130576777.

It is an arithmetic number, because the mean of its divisors is an integer number (130576777).

Almost surely, 2^261153553 is an apocalyptic number.

It is an amenable number.

261153553 is a deficient number, since it is larger than the sum of its proper divisors (1).

261153553 is an equidigital number, since it uses as much as digits as its factorization.

261153553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13500, while the sum is 31.

The square root of 261153553 is about 16160.2460686711. The cubic root of 261153553 is about 639.1929549055.

The spelling of 261153553 in words is "two hundred sixty-one million, one hundred fifty-three thousand, five hundred fifty-three".