261388697 has 2 divisors, whose sum is σ = 261388698. Its totient is φ = 261388696.

The previous prime is 261388679. The next prime is 261388711. The reversal of 261388697 is 796883162.

Together with previous prime (261388679) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174134416 + 87254281 = 13196^2 + 9341^2 .

It is a cyclic number.

It is not a de Polignac number, because 261388697 - 2⁸ = 261388441 is a prime.

It is not a weakly prime, because it can be changed into another prime (261388607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130694348 + 130694349.

It is an arithmetic number, because the mean of its divisors is an integer number (130694349).

Almost surely, 2^261388697 is an apocalyptic number.

It is an amenable number.

261388697 is a deficient number, since it is larger than the sum of its proper divisors (1).

261388697 is an equidigital number, since it uses as much as digits as its factorization.

261388697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 50.

The square root of 261388697 is about 16167.5198159767. The cubic root of 261388697 is about 639.3847415612.

The spelling of 261388697 in words is "two hundred sixty-one million, three hundred eighty-eight thousand, six hundred ninety-seven".