398830918021 has 2 divisors, whose sum is σ = 398830918022. Its totient is φ = 398830918020.

The previous prime is 398830917937. The next prime is 398830918039. The reversal of 398830918021 is 120819038893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 270931701121 + 127899216900 = 520511^2 + 357630^2 .

It is a cyclic number.

It is not a de Polignac number, because 398830918021 - 2⁹ = 398830917509 is a prime.

It is a super-2 number, since 2×398830918021² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 398830918021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398830918061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199415459010 + 199415459011.

It is an arithmetic number, because the mean of its divisors is an integer number (199415459011).

Almost surely, 2^398830918021 is an apocalyptic number.

It is an amenable number.

398830918021 is a deficient number, since it is larger than the sum of its proper divisors (1).

398830918021 is an equidigital number, since it uses as much as digits as its factorization.

398830918021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 746496, while the sum is 52.

The spelling of 398830918021 in words is "three hundred ninety-eight billion, eight hundred thirty million, nine hundred eighteen thousand, twenty-one".