1220021009 has 2 divisors, whose sum is σ = 1220021010. Its totient is φ = 1220021008.

The previous prime is 1220020987. The next prime is 1220021029. The reversal of 1220021009 is 9001200221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1207771009 + 12250000 = 34753^2 + 3500^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220021009 - 2¹² = 1220016913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1220021029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610010504 + 610010505.

It is an arithmetic number, because the mean of its divisors is an integer number (610010505).

Almost surely, 2^1220021009 is an apocalyptic number.

It is an amenable number.

1220021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220021009 is an equidigital number, since it uses as much as digits as its factorization.

1220021009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1220021009 is about 34928.7991348114. The cubic root of 1220021009 is about 1068.5358636495.

The spelling of 1220021009 in words is "one billion, two hundred twenty million, twenty-one thousand, nine".