1228406821 has 2 divisors, whose sum is σ = 1228406822. Its totient is φ = 1228406820.

The previous prime is 1228406813. The next prime is 1228406831. The reversal of 1228406821 is 1286048221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 753777025 + 474629796 = 27455^2 + 21786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1228406821 - 2³ = 1228406813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1228406831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 614203410 + 614203411.

It is an arithmetic number, because the mean of its divisors is an integer number (614203411).

Almost surely, 2^1228406821 is an apocalyptic number.

It is an amenable number.

1228406821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1228406821 is an equidigital number, since it uses as much as digits as its factorization.

1228406821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 1228406821 is about 35048.6350804136. The cubic root of 1228406821 is about 1070.9784688052.

The spelling of 1228406821 in words is "one billion, two hundred twenty-eight million, four hundred six thousand, eight hundred twenty-one".