261870001 has 2 divisors, whose sum is σ = 261870002. Its totient is φ = 261870000.

The previous prime is 261869987. The next prime is 261870017. The reversal of 261870001 is 100078162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261662976 + 207025 = 16176^2 + 455^2 .

It is a cyclic number.

It is not a de Polignac number, because 261870001 - 2¹¹ = 261867953 is a prime.

It is not a weakly prime, because it can be changed into another prime (261870031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130935000 + 130935001.

It is an arithmetic number, because the mean of its divisors is an integer number (130935001).

Almost surely, 2^261870001 is an apocalyptic number.

It is an amenable number.

261870001 is a deficient number, since it is larger than the sum of its proper divisors (1).

261870001 is an equidigital number, since it uses as much as digits as its factorization.

261870001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 261870001 is about 16182.3978754695. The cubic root of 261870001 is about 639.7769413095.

The spelling of 261870001 in words is "two hundred sixty-one million, eight hundred seventy thousand, one".