1809297121 has 2 divisors, whose sum is σ = 1809297122. Its totient is φ = 1809297120.

The previous prime is 1809297103. The next prime is 1809297187. The reversal of 1809297121 is 1217929081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1226750625 + 582546496 = 35025^2 + 24136^2 .

It is a cyclic number.

It is not a de Polignac number, because 1809297121 - 2⁵ = 1809297089 is a prime.

It is not a weakly prime, because it can be changed into another prime (1809207121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 904648560 + 904648561.

It is an arithmetic number, because the mean of its divisors is an integer number (904648561).

Almost surely, 2^1809297121 is an apocalyptic number.

It is an amenable number.

1809297121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1809297121 is an equidigital number, since it uses as much as digits as its factorization.

1809297121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 40.

The square root of 1809297121 is about 42535.8333761077. The cubic root of 1809297121 is about 1218.5311357816.

The spelling of 1809297121 in words is "one billion, eight hundred nine million, two hundred ninety-seven thousand, one hundred twenty-one".