1820403121 has 2 divisors, whose sum is σ = 1820403122. Its totient is φ = 1820403120.

The previous prime is 1820403113. The next prime is 1820403127. The reversal of 1820403121 is 1213040281.

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., 1689621025 + 130782096 = 41105^2 + 11436^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820403121 - 2³ = 1820403113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1820403092 and 1820403101.

It is not a weakly prime, because it can be changed into another prime (1820403127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910201560 + 910201561.

It is an arithmetic number, because the mean of its divisors is an integer number (910201561).

Almost surely, 2^1820403121 is an apocalyptic number.

It is an amenable number.

1820403121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820403121 is an equidigital number, since it uses as much as digits as its factorization.

1820403121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1820403121 is about 42666.1824048039. The cubic root of 1820403121 is about 1221.0192863486.

The spelling of 1820403121 in words is "one billion, eight hundred twenty million, four hundred three thousand, one hundred twenty-one".