261800117 has 2 divisors, whose sum is σ = 261800118. Its totient is φ = 261800116.

The previous prime is 261800093. The next prime is 261800131. The reversal of 261800117 is 711008162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204661636 + 57138481 = 14306^2 + 7559^2 .

It is a cyclic number.

It is not a de Polignac number, because 261800117 - 2¹⁴ = 261783733 is a prime.

It is a super-2 number, since 2×261800117² = 137078602522427378, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261800137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130900058 + 130900059.

It is an arithmetic number, because the mean of its divisors is an integer number (130900059).

Almost surely, 2^261800117 is an apocalyptic number.

It is an amenable number.

261800117 is a deficient number, since it is larger than the sum of its proper divisors (1).

261800117 is an equidigital number, since it uses as much as digits as its factorization.

261800117 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 26.

The square root of 261800117 is about 16180.2384716666. The cubic root of 261800117 is about 639.7200248378.

Adding to 261800117 its reverse (711008162), we get a palindrome (972808279).

The spelling of 261800117 in words is "two hundred sixty-one million, eight hundred thousand, one hundred seventeen".