261505507 has 2 divisors, whose sum is σ = 261505508. Its totient is φ = 261505506.

The previous prime is 261505487. The next prime is 261505513. The reversal of 261505507 is 705505162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261505507 - 2²⁷ = 127287779 is a prime.

It is not a weakly prime, because it can be changed into another prime (261505547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130752753 + 130752754.

It is an arithmetic number, because the mean of its divisors is an integer number (130752754).

Almost surely, 2^261505507 is an apocalyptic number.

261505507 is a deficient number, since it is larger than the sum of its proper divisors (1).

261505507 is an equidigital number, since it uses as much as digits as its factorization.

261505507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 261505507 is about 16171.1319022510. The cubic root of 261505507 is about 639.4799706331.

The spelling of 261505507 in words is "two hundred sixty-one million, five hundred five thousand, five hundred seven".