1818402121 has 2 divisors, whose sum is σ = 1818402122. Its totient is φ = 1818402120.

The previous prime is 1818402077. The next prime is 1818402169. The reversal of 1818402121 is 1212048181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1300612096 + 517790025 = 36064^2 + 22755^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1818402121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1818402121.

It is not a weakly prime, because it can be changed into another prime (1818402181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909201060 + 909201061.

It is an arithmetic number, because the mean of its divisors is an integer number (909201061).

Almost surely, 2^1818402121 is an apocalyptic number.

It is an amenable number.

1818402121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818402121 is an equidigital number, since it uses as much as digits as its factorization.

1818402121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1024, while the sum is 28.

The square root of 1818402121 is about 42642.7264724009. The cubic root of 1818402121 is about 1220.5717379774.

The spelling of 1818402121 in words is "one billion, eight hundred eighteen million, four hundred two thousand, one hundred twenty-one".