261535663 has 2 divisors, whose sum is σ = 261535664. Its totient is φ = 261535662.

The previous prime is 261535661. The next prime is 261535669. The reversal of 261535663 is 366535162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261535663 - 2¹ = 261535661 is a prime.

Together with 261535661, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261535661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130767831 + 130767832.

It is an arithmetic number, because the mean of its divisors is an integer number (130767832).

Almost surely, 2^261535663 is an apocalyptic number.

261535663 is a deficient number, since it is larger than the sum of its proper divisors (1).

261535663 is an equidigital number, since it uses as much as digits as its factorization.

261535663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 97200, while the sum is 37.

The square root of 261535663 is about 16172.0642776363. The cubic root of 261535663 is about 639.5045506340.

The spelling of 261535663 in words is "two hundred sixty-one million, five hundred thirty-five thousand, six hundred sixty-three".