261910897 has 2 divisors, whose sum is σ = 261910898. Its totient is φ = 261910896.

The previous prime is 261910871. The next prime is 261910967. The reversal of 261910897 is 798019162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156725361 + 105185536 = 12519^2 + 10256^2 .

It is a cyclic number.

It is not a de Polignac number, because 261910897 - 2¹¹ = 261908849 is a prime.

It is not a weakly prime, because it can be changed into another prime (261910097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130955448 + 130955449.

It is an arithmetic number, because the mean of its divisors is an integer number (130955449).

Almost surely, 2^261910897 is an apocalyptic number.

It is an amenable number.

261910897 is a deficient number, since it is larger than the sum of its proper divisors (1).

261910897 is an equidigital number, since it uses as much as digits as its factorization.

261910897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 43.

The square root of 261910897 is about 16183.6614213224. The cubic root of 261910897 is about 639.8102440371.

The spelling of 261910897 in words is "two hundred sixty-one million, nine hundred ten thousand, eight hundred ninety-seven".