21175806644 has 12 divisors (see below), whose sum is σ = 37059974784. Its totient is φ = 10587242424.

The previous prime is 21175806629. The next prime is 21175806671. The reversal of 21175806644 is 44660857112.

It is a junction number, because it is equal to n+sod(n) for n = 21175806595 and 21175806604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89252 + ... + 224315.

It is an arithmetic number, because the mean of its divisors is an integer number (3088331232).

Almost surely, 2^21175806644 is an apocalyptic number.

It is an amenable number.

21175806644 is a deficient number, since it is larger than the sum of its proper divisors (15884168140).

21175806644 is a wasteful number, since it uses less digits than its factorization.

21175806644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330454 (or 330452 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 44.

The spelling of 21175806644 in words is "twenty-one billion, one hundred seventy-five million, eight hundred six thousand, six hundred forty-four".