21606546644 has 24 divisors (see below), whose sum is σ = 40040192808. Its totient is φ = 10166635520.

The previous prime is 21606546613. The next prime is 21606546653. The reversal of 21606546644 is 44664560612.

It can be written as a sum of positive squares in 4 ways, for example, as 4272191044 + 17334355600 = 65362^2 + 131660^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21606546595 and 21606546604.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1049312 + ... + 1069704.

It is an arithmetic number, because the mean of its divisors is an integer number (1668341367).

Almost surely, 2^21606546644 is an apocalyptic number.

It is an amenable number.

21606546644 is a deficient number, since it is larger than the sum of its proper divisors (18433646164).

21606546644 is a wasteful number, since it uses less digits than its factorization.

21606546644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35995 (or 35993 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 44.

The spelling of 21606546644 in words is "twenty-one billion, six hundred six million, five hundred forty-six thousand, six hundred forty-four".