20644653228 has 12 divisors (see below), whose sum is σ = 48170857560. Its totient is φ = 6881551072.

The previous prime is 20644653209. The next prime is 20644653343. The reversal of 20644653228 is 82235644602.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 20644653228.

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, 860193873 + ... + 860193896.

It is an arithmetic number, because the mean of its divisors is an integer number (4014238130).

Almost surely, 2^20644653228 is an apocalyptic number.

It is an amenable number.

20644653228 is an abundant number, since it is smaller than the sum of its proper divisors (27526204332).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20644653228 is a wasteful number, since it uses less digits than its factorization.

20644653228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1720387776 (or 1720387774 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 42.

The spelling of 20644653228 in words is "twenty billion, six hundred forty-four million, six hundred fifty-three thousand, two hundred twenty-eight".