18643405475601 has 9 divisors (see below), whose sum is σ = 26929382175241. Its totient is φ = 12428928348132.

The previous prime is 18643405475483. The next prime is 18643405475609. The reversal of 18643405475601 is 10657450434681.

The square root of 18643405475601 is 4317801.

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

18643405475601 is a `hidden beast` number, since 1 + 8 + 6 + 4 + 3 + 40 + 547 + 56 + 0 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 18643405475601 - 2⁷ = 18643405475473 is a prime.

It is a super-2 number, since 2×18643405475601² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18643405475609) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12233770 + ... + 13673036.

Almost surely, 2^{18643405475601} is an apocalyptic number.

18643405475601 is the 4317801-st square number.

18643405475601 is the 2158901-st centered octagonal number.

It is an amenable number.

18643405475601 is a deficient number, since it is larger than the sum of its proper divisors (8285976699640).

18643405475601 is an frugal number, since it uses more digits than its factorization.

18643405475601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2878540 (or 1439270 counting only the distinct ones).

The product of its (nonzero) digits is 9676800, while the sum is 54.

The spelling of 18643405475601 in words is "eighteen trillion, six hundred forty-three billion, four hundred five million, four hundred seventy-five thousand, six hundred one".