21604635005641 has 4 divisors (see below), whose sum is σ = 22543966962432. Its totient is φ = 20665303048852.

The previous prime is 21604635005617. The next prime is 21604635005711. The reversal of 21604635005641 is 14650053640612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21604635005641 - 2¹⁷ = 21604634874569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21604635005741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 469665978361 + ... + 469665978406.

It is an arithmetic number, because the mean of its divisors is an integer number (5635991740608).

Almost surely, 2^{21604635005641} is an apocalyptic number.

It is an amenable number.

21604635005641 is a deficient number, since it is larger than the sum of its proper divisors (939331956791).

21604635005641 is an equidigital number, since it uses as much as digits as its factorization.

21604635005641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 939331956790.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 21604635005641 in words is "twenty-one trillion, six hundred four billion, six hundred thirty-five million, five thousand, six hundred forty-one".