201665564556 has 48 divisors (see below), whose sum is σ = 507633213024. Its totient is φ = 62073895936.

The previous prime is 201665564447. The next prime is 201665564557. The reversal of 201665564556 is 655465566102.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a junction number, because it is equal to n+sod(n) for n = 201665564499 and 201665564508.

It is not an unprimeable number, because it can be changed into a prime (201665564557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9315195 + ... + 9336818.

It is an arithmetic number, because the mean of its divisors is an integer number (10575691938).

Almost surely, 2^201665564556 is an apocalyptic number.

It is an amenable number.

201665564556 is an abundant number, since it is smaller than the sum of its proper divisors (305967648468).

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

201665564556 is a wasteful number, since it uses less digits than its factorization.

201665564556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18652090 (or 18652088 counting only the distinct ones).

The product of its (nonzero) digits is 6480000, while the sum is 51.

The spelling of 201665564556 in words is "two hundred one billion, six hundred sixty-five million, five hundred sixty-four thousand, five hundred fifty-six".