1209403121 has 2 divisors, whose sum is σ = 1209403122. Its totient is φ = 1209403120.

The previous prime is 1209403087. The next prime is 1209403123. The reversal of 1209403121 is 1213049021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 935136400 + 274266721 = 30580^2 + 16561^2 .

It is a cyclic number.

It is not a de Polignac number, because 1209403121 - 2⁶ = 1209403057 is a prime.

Together with 1209403123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1209403123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 604701560 + 604701561.

It is an arithmetic number, because the mean of its divisors is an integer number (604701561).

Almost surely, 2^1209403121 is an apocalyptic number.

It is an amenable number.

1209403121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1209403121 is an equidigital number, since it uses as much as digits as its factorization.

1209403121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1209403121 is about 34776.4736711473. The cubic root of 1209403121 is about 1065.4269915299.

The spelling of 1209403121 in words is "one billion, two hundred nine million, four hundred three thousand, one hundred twenty-one".