263520561 has 4 divisors (see below), whose sum is σ = 351360752. Its totient is φ = 175680372.

The previous prime is 263520541. The next prime is 263520589. The reversal of 263520561 is 165025362.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 263520561 - 2¹⁰ = 263519537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (263520541) 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 in 3 ways as a sum of consecutive naturals, for example, 43920091 + ... + 43920096.

It is an arithmetic number, because the mean of its divisors is an integer number (87840188).

Almost surely, 2^263520561 is an apocalyptic number.

It is an amenable number.

263520561 is a deficient number, since it is larger than the sum of its proper divisors (87840191).

263520561 is an equidigital number, since it uses as much as digits as its factorization.

263520561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87840190.

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 263520561 is about 16233.3163894504. The cubic root of 263520561 is about 641.1182930413.

The spelling of 263520561 in words is "two hundred sixty-three million, five hundred twenty thousand, five hundred sixty-one".