264641561 has 4 divisors (see below), whose sum is σ = 269634852. Its totient is φ = 259648272.

The previous prime is 264641497. The next prime is 264641563. The reversal of 264641561 is 165146462.

264641561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 236083225 + 28558336 = 15365^2 + 5344^2 .

It is not a de Polignac number, because 264641561 - 2⁶ = 264641497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (264641563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2496566 + ... + 2496671.

It is an arithmetic number, because the mean of its divisors is an integer number (67408713).

Almost surely, 2^264641561 is an apocalyptic number.

It is an amenable number.

264641561 is a deficient number, since it is larger than the sum of its proper divisors (4993291).

264641561 is an equidigital number, since it uses as much as digits as its factorization.

264641561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4993290.

The product of its digits is 34560, while the sum is 35.

The square root of 264641561 is about 16267.8075043935. The cubic root of 264641561 is about 642.0260993909.

The spelling of 264641561 in words is "two hundred sixty-four million, six hundred forty-one thousand, five hundred sixty-one".