163994890990401 has 27 divisors (see below), whose sum is σ = 251636376973891. Its totient is φ = 102898345337664.

The previous prime is 163994890990393. The next prime is 163994890990423. The reversal of 163994890990401 is 104099098499361.

The square root of 163994890990401 is 12806049.

It is a perfect power (a square), and thus also a powerful number.

163994890990401 is a `hidden beast` number, since 1 + 6 + 3 + 9 + 9 + 48 + 90 + 9 + 90 + 401 = 666.

It can be written as a sum of positive squares in only one way, i.e., 127677683297025 + 36317207693376 = 11299455^2 + 6026376^2 .

It is not a de Polignac number, because 163994890990401 - 2³ = 163994890990393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 163994890990401.

It is not an unprimeable number, because it can be changed into a prime (163994890990501) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 652982950 + ... + 653234048.

Almost surely, 2^{163994890990401} is an apocalyptic number.

163994890990401 is the 12806049-th square number.

163994890990401 is the 6403025-th centered octagonal number.

It is an amenable number.

163994890990401 is a deficient number, since it is larger than the sum of its proper divisors (87641485983490).

163994890990401 is an frugal number, since it uses more digits than its factorization.

163994890990401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502238 (or 251119 counting only the distinct ones).

The product of its (nonzero) digits is 136048896, while the sum is 72.

The spelling of 163994890990401 in words is "one hundred sixty-three trillion, nine hundred ninety-four billion, eight hundred ninety million, nine hundred ninety thousand, four hundred one".