261488641 has 2 divisors, whose sum is σ = 261488642. Its totient is φ = 261488640.

The previous prime is 261488609. The next prime is 261488653. The reversal of 261488641 is 146884162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161188416 + 100300225 = 12696^2 + 10015^2 .

It is a cyclic number.

It is not a de Polignac number, because 261488641 - 2⁵ = 261488609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261488594 and 261488603.

It is not a weakly prime, because it can be changed into another prime (261488671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130744320 + 130744321.

It is an arithmetic number, because the mean of its divisors is an integer number (130744321).

It is a Proth number, since it is equal to 1995 ⋅ 2¹⁷ + 1 and 1995 < 2¹⁷.

Almost surely, 2^261488641 is an apocalyptic number.

It is an amenable number.

261488641 is a deficient number, since it is larger than the sum of its proper divisors (1).

261488641 is an equidigital number, since it uses as much as digits as its factorization.

261488641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 73728, while the sum is 40.

The square root of 261488641 is about 16170.6104090105. The cubic root of 261488641 is about 639.4662224191.

The spelling of 261488641 in words is "two hundred sixty-one million, four hundred eighty-eight thousand, six hundred forty-one".