21220856704 has 32 divisors (see below), whose sum is σ = 42284040840. Its totient is φ = 10608391680.

The previous prime is 21220856639. The next prime is 21220856773. The reversal of 21220856704 is 40765802212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

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, 827434 + ... + 852694.

Almost surely, 2^21220856704 is an apocalyptic number.

It is an amenable number.

21220856704 is a deficient number, since it is larger than the sum of its proper divisors (21063184136).

21220856704 is an equidigital number, since it uses as much as digits as its factorization.

21220856704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31838 (or 31826 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 37.

The spelling of 21220856704 in words is "twenty-one billion, two hundred twenty million, eight hundred fifty-six thousand, seven hundred four".