261806807 has 2 divisors, whose sum is σ = 261806808. Its totient is φ = 261806806.

The previous prime is 261806801. The next prime is 261806821. The reversal of 261806807 is 708608162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261806807 - 2⁴ = 261806791 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261806801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130903403 + 130903404.

It is an arithmetic number, because the mean of its divisors is an integer number (130903404).

Almost surely, 2^261806807 is an apocalyptic number.

261806807 is a deficient number, since it is larger than the sum of its proper divisors (1).

261806807 is an equidigital number, since it uses as much as digits as its factorization.

261806807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 261806807 is about 16180.4452040109. The cubic root of 261806807 is about 639.7254738938.

The spelling of 261806807 in words is "two hundred sixty-one million, eight hundred six thousand, eight hundred seven".