1280688821 has 2 divisors, whose sum is σ = 1280688822. Its totient is φ = 1280688820.

The previous prime is 1280688817. The next prime is 1280688911. The reversal of 1280688821 is 1288860821.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 813048196 + 467640625 = 28514^2 + 21625^2 .

It is a cyclic number.

It is not a de Polignac number, because 1280688821 - 2² = 1280688817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1280685821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640344410 + 640344411.

It is an arithmetic number, because the mean of its divisors is an integer number (640344411).

Almost surely, 2^1280688821 is an apocalyptic number.

It is an amenable number.

1280688821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1280688821 is an equidigital number, since it uses as much as digits as its factorization.

1280688821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 98304, while the sum is 44.

The square root of 1280688821 is about 35786.7129113586. The cubic root of 1280688821 is about 1085.9617771131.

The spelling of 1280688821 in words is "one billion, two hundred eighty million, six hundred eighty-eight thousand, eight hundred twenty-one".