1663973582401 has 27 divisors (see below), whose sum is σ = 1830347617833. Its totient is φ = 1512028964160.

The previous prime is 1663973582377. The next prime is 1663973582489. The reversal of 1663973582401 is 1042853793661.

It is a happy number.

The square root of 1663973582401 is 1289951.

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

It can be written as a sum of positive squares in 4 ways, for example, as 331620498225 + 1332353084176 = 575865^2 + 1154276^2 .

It is not a de Polignac number, because 1663973582401 - 2¹³ = 1663973574209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1663973583401) 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 in 26 ways as a sum of consecutive naturals, for example, 1123546581 + ... + 1123548061.

It is a 1-persistent number, because it is pandigital, but 2⋅1663973582401 = 3327947164802 is not.

Almost surely, 2^{1663973582401} is an apocalyptic number.

1663973582401 is the 1289951-st square number.

1663973582401 is the 644976-th centered octagonal number.

It is an amenable number.

1663973582401 is a deficient number, since it is larger than the sum of its proper divisors (166374035432).

1663973582401 is an frugal number, since it uses more digits than its factorization.

1663973582401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3122 (or 1561 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 55.

The spelling of 1663973582401 in words is "one trillion, six hundred sixty-three billion, nine hundred seventy-three million, five hundred eighty-two thousand, four hundred one".