21606325641 has 10 divisors (see below), whose sum is σ = 32276116202. Its totient is φ = 14404217040.

The previous prime is 21606325633. The next prime is 21606325709. The reversal of 21606325641 is 14652360612.

21606325641 is a `hidden beast` number, since 2 + 1 + 6 + 0 + 6 + 3 + 2 + 5 + 641 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14382005625 + 7224320016 = 119925^2 + 84996^2 .

It is not a de Polignac number, because 21606325641 - 2³ = 21606325633 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21606325596 and 21606325605.

It is not an unprimeable number, because it can be changed into a prime (21606320641) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 133372300 + ... + 133372461.

Almost surely, 2^21606325641 is an apocalyptic number.

It is an amenable number.

21606325641 is a deficient number, since it is larger than the sum of its proper divisors (10669790561).

21606325641 is an equidigital number, since it uses as much as digits as its factorization.

21606325641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266744773 (or 266744764 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21606325641 in words is "twenty-one billion, six hundred six million, three hundred twenty-five thousand, six hundred forty-one".