1200001001 has 2 divisors, whose sum is σ = 1200001002. Its totient is φ = 1200001000.

The previous prime is 1200000961. The next prime is 1200001009. The reversal of 1200001001 is 1001000021.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 874739776 + 325261225 = 29576^2 + 18035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1200001001 is a prime.

It is not a weakly prime, because it can be changed into another prime (1200001009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 600000500 + 600000501.

It is an arithmetic number, because the mean of its divisors is an integer number (600000501).

Almost surely, 2^1200001001 is an apocalyptic number.

It is an amenable number.

1200001001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200001001 is an equidigital number, since it uses as much as digits as its factorization.

1200001001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 1200001001 is about 34641.0305995650. The cubic root of 1200001001 is about 1062.6588646606.

Adding to 1200001001 its reverse (1001000021), we get a palindrome (2201001022).

The spelling of 1200001001 in words is "one billion, two hundred million, one thousand, one".