21603636673 has 16 divisors (see below), whose sum is σ = 22667299200. Its totient is φ = 20550625920.

The previous prime is 21603636653. The next prime is 21603636679. The reversal of 21603636673 is 37663630612.

It is a cyclic number.

It is not a de Polignac number, because 21603636673 - 2⁵ = 21603636641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21603636679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3826933 + ... + 3832573.

It is an arithmetic number, because the mean of its divisors is an integer number (1416706200).

Almost surely, 2^21603636673 is an apocalyptic number.

21603636673 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21603636673 is a deficient number, since it is larger than the sum of its proper divisors (1063662527).

21603636673 is a wasteful number, since it uses less digits than its factorization.

21603636673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6552.

The product of its (nonzero) digits is 489888, while the sum is 43.

The spelling of 21603636673 in words is "twenty-one billion, six hundred three million, six hundred thirty-six thousand, six hundred seventy-three".