261505711 has 2 divisors, whose sum is σ = 261505712. Its totient is φ = 261505710.

The previous prime is 261505691. The next prime is 261505787. The reversal of 261505711 is 117505162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261505711 - 2⁷ = 261505583 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261505711.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261505411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130752855 + 130752856.

It is an arithmetic number, because the mean of its divisors is an integer number (130752856).

Almost surely, 2^261505711 is an apocalyptic number.

261505711 is a deficient number, since it is larger than the sum of its proper divisors (1).

261505711 is an equidigital number, since it uses as much as digits as its factorization.

261505711 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2100, while the sum is 28.

The square root of 261505711 is about 16171.1382097860. The cubic root of 261505711 is about 639.4801369188.

The spelling of 261505711 in words is "two hundred sixty-one million, five hundred five thousand, seven hundred eleven".