1838521021 has 2 divisors, whose sum is σ = 1838521022. Its totient is φ = 1838521020.

The previous prime is 1838521019. The next prime is 1838521039. The reversal of 1838521021 is 1201258381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1536248025 + 302272996 = 39195^2 + 17386^2 .

It is a cyclic number.

It is not a de Polignac number, because 1838521021 - 2¹ = 1838521019 is a prime.

Together with 1838521019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1838521621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 919260510 + 919260511.

It is an arithmetic number, because the mean of its divisors is an integer number (919260511).

Almost surely, 2^1838521021 is an apocalyptic number.

It is an amenable number.

1838521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1838521021 is an equidigital number, since it uses as much as digits as its factorization.

1838521021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 1838521021 is about 42877.9782755671. The cubic root of 1838521021 is about 1225.0567284017.

The spelling of 1838521021 in words is "one billion, eight hundred thirty-eight million, five hundred twenty-one thousand, twenty-one".