261323653 has 4 divisors (see below), whose sum is σ = 261363628. Its totient is φ = 261283680.

The previous prime is 261323641. The next prime is 261323681. The reversal of 261323653 is 356323162.

It is a happy number.

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 115928289 + 145395364 = 10767^2 + 12058^2 .

It is a cyclic number.

It is not a de Polignac number, because 261323653 - 2²⁵ = 227769221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261323603) 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 in 3 ways as a sum of consecutive naturals, for example, 7638 + ... + 24103.

It is an arithmetic number, because the mean of its divisors is an integer number (65340907).

Almost surely, 2^261323653 is an apocalyptic number.

It is an amenable number.

261323653 is a deficient number, since it is larger than the sum of its proper divisors (39975).

261323653 is an equidigital number, since it uses as much as digits as its factorization.

261323653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39974.

The product of its digits is 19440, while the sum is 31.

The square root of 261323653 is about 16165.5081268731. The cubic root of 261323653 is about 639.3317022987.

The spelling of 261323653 in words is "two hundred sixty-one million, three hundred twenty-three thousand, six hundred fifty-three".