261231697 has 2 divisors, whose sum is σ = 261231698. Its totient is φ = 261231696.

The previous prime is 261231679. The next prime is 261231757. The reversal of 261231697 is 796132162.

Together with previous prime (261231679) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 142181776 + 119049921 = 11924^2 + 10911^2 .

It is a cyclic number.

It is not a de Polignac number, because 261231697 - 2¹¹ = 261229649 is a prime.

It is not a weakly prime, because it can be changed into another prime (261231617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130615848 + 130615849.

It is an arithmetic number, because the mean of its divisors is an integer number (130615849).

Almost surely, 2^261231697 is an apocalyptic number.

It is an amenable number.

261231697 is a deficient number, since it is larger than the sum of its proper divisors (1).

261231697 is an equidigital number, since it uses as much as digits as its factorization.

261231697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 37.

The square root of 261231697 is about 16162.6636727985. The cubic root of 261231697 is about 639.2567029858.

The spelling of 261231697 in words is "two hundred sixty-one million, two hundred thirty-one thousand, six hundred ninety-seven".