261630653 has 2 divisors, whose sum is σ = 261630654. Its totient is φ = 261630652.

The previous prime is 261630641. The next prime is 261630659. The reversal of 261630653 is 356036162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145033849 + 116596804 = 12043^2 + 10798^2 .

It is a cyclic number.

It is not a de Polignac number, because 261630653 - 2⁴ = 261630637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261630659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130815326 + 130815327.

It is an arithmetic number, because the mean of its divisors is an integer number (130815327).

Almost surely, 2^261630653 is an apocalyptic number.

It is an amenable number.

261630653 is a deficient number, since it is larger than the sum of its proper divisors (1).

261630653 is an equidigital number, since it uses as much as digits as its factorization.

261630653 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 261630653 is about 16175.0008655332. Note that the first 3 decimals coincide. The cubic root of 261630653 is about 639.5819641483.

The spelling of 261630653 in words is "two hundred sixty-one million, six hundred thirty thousand, six hundred fifty-three".