1221400409 has 2 divisors, whose sum is σ = 1221400410. Its totient is φ = 1221400408.

The previous prime is 1221400339. The next prime is 1221400417. The reversal of 1221400409 is 9040041221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 683299600 + 538100809 = 26140^2 + 23197^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221400409 - 2⁸ = 1221400153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221400469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610700204 + 610700205.

It is an arithmetic number, because the mean of its divisors is an integer number (610700205).

Almost surely, 2^1221400409 is an apocalyptic number.

It is an amenable number.

1221400409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221400409 is an equidigital number, since it uses as much as digits as its factorization.

1221400409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1221400409 is about 34948.5394401540. The cubic root of 1221400409 is about 1068.9384204394.

The spelling of 1221400409 in words is "one billion, two hundred twenty-one million, four hundred thousand, four hundred nine".