260691000721 has 2 divisors, whose sum is σ = 260691000722. Its totient is φ = 260691000720.

The previous prime is 260691000641. The next prime is 260691000761. The reversal of 260691000721 is 127000196062.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154398700096 + 106292300625 = 392936^2 + 326025^2 .

It is a cyclic number.

It is not a de Polignac number, because 260691000721 - 2⁹ = 260691000209 is a prime.

It is not a weakly prime, because it can be changed into another prime (260691000761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130345500360 + 130345500361.

It is an arithmetic number, because the mean of its divisors is an integer number (130345500361).

Almost surely, 2^260691000721 is an apocalyptic number.

It is an amenable number.

260691000721 is a deficient number, since it is larger than the sum of its proper divisors (1).

260691000721 is an equidigital number, since it uses as much as digits as its factorization.

260691000721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 34.

Adding to 260691000721 its reverse (127000196062), we get a palindrome (387691196783).

The spelling of 260691000721 in words is "two hundred sixty billion, six hundred ninety-one million, seven hundred twenty-one", and thus it is an aban number.