261669497 has 2 divisors, whose sum is σ = 261669498. Its totient is φ = 261669496.

The previous prime is 261669437. The next prime is 261669511. The reversal of 261669497 is 794966162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 254211136 + 7458361 = 15944^2 + 2731^2 .

It is a cyclic number.

It is not a de Polignac number, because 261669497 - 2¹⁶ = 261603961 is a prime.

It is not a weakly prime, because it can be changed into another prime (261669437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130834748 + 130834749.

It is an arithmetic number, because the mean of its divisors is an integer number (130834749).

Almost surely, 2^261669497 is an apocalyptic number.

It is an amenable number.

261669497 is a deficient number, since it is larger than the sum of its proper divisors (1).

261669497 is an equidigital number, since it uses as much as digits as its factorization.

261669497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 50.

The square root of 261669497 is about 16176.2015627897. The cubic root of 261669497 is about 639.6136152464.

The spelling of 261669497 in words is "two hundred sixty-one million, six hundred sixty-nine thousand, four hundred ninety-seven".