261807401 has 2 divisors, whose sum is σ = 261807402. Its totient is φ = 261807400.

The previous prime is 261807397. The next prime is 261807407. The reversal of 261807401 is 104708162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211411600 + 50395801 = 14540^2 + 7099^2 .

It is a cyclic number.

It is not a de Polignac number, because 261807401 - 2² = 261807397 is a prime.

It is not a weakly prime, because it can be changed into another prime (261807407) 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, 130903700 + 130903701.

It is an arithmetic number, because the mean of its divisors is an integer number (130903701).

Almost surely, 2^261807401 is an apocalyptic number.

It is an amenable number.

261807401 is a deficient number, since it is larger than the sum of its proper divisors (1).

261807401 is an equidigital number, since it uses as much as digits as its factorization.

261807401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 261807401 is about 16180.4635594905. The cubic root of 261807401 is about 639.7259577068.

The spelling of 261807401 in words is "two hundred sixty-one million, eight hundred seven thousand, four hundred one".