1200400121 has 2 divisors, whose sum is σ = 1200400122. Its totient is φ = 1200400120.

The previous prime is 1200400093. The next prime is 1200400129. The reversal of 1200400121 is 1210040021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 689640121 + 510760000 = 26261^2 + 22600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1200400121 - 2²² = 1196205817 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1200400129) 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, 600200060 + 600200061.

It is an arithmetic number, because the mean of its divisors is an integer number (600200061).

Almost surely, 2^1200400121 is an apocalyptic number.

It is an amenable number.

1200400121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200400121 is an equidigital number, since it uses as much as digits as its factorization.

1200400121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1200400121 is about 34646.7909192179. The cubic root of 1200400121 is about 1062.7766649494.

Adding to 1200400121 its reverse (1210040021), we get a palindrome (2410440142).

The spelling of 1200400121 in words is "one billion, two hundred million, four hundred thousand, one hundred twenty-one".