261003641 has 4 divisors (see below), whose sum is σ = 265928292. Its totient is φ = 256078992.

The previous prime is 261003637. The next prime is 261003647. The reversal of 261003641 is 146300162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 146300162 = 2 ⋅73150081.

It can be written as a sum of positive squares in 2 ways, for example, as 230918416 + 30085225 = 15196^2 + 5485^2 .

It is a cyclic number.

It is not a de Polignac number, because 261003641 - 2² = 261003637 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261003647) 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, 2462246 + ... + 2462351.

It is an arithmetic number, because the mean of its divisors is an integer number (66482073).

Almost surely, 2^261003641 is an apocalyptic number.

It is an amenable number.

261003641 is a deficient number, since it is larger than the sum of its proper divisors (4924651).

261003641 is an equidigital number, since it uses as much as digits as its factorization.

261003641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4924650.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 261003641 is about 16155.6071071316. The cubic root of 261003641 is about 639.0706245315.

The spelling of 261003641 in words is "two hundred sixty-one million, three thousand, six hundred forty-one".