20664533628 has 18 divisors (see below), whose sum is σ = 52235348984. Its totient is φ = 6888177864.

The previous prime is 20664533621. The next prime is 20664533657. The reversal of 20664533628 is 82633546602.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20664533621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 287007376 + ... + 287007447.

Almost surely, 2^20664533628 is an apocalyptic number.

It is an amenable number.

20664533628 is an abundant number, since it is smaller than the sum of its proper divisors (31570815356).

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

20664533628 is a wasteful number, since it uses less digits than its factorization.

20664533628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574014833 (or 574014828 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 20664533628 in words is "twenty billion, six hundred sixty-four million, five hundred thirty-three thousand, six hundred twenty-eight".