201665664 has 96 divisors (see below), whose sum is σ = 599139840. Its totient is φ = 65041920.

The previous prime is 201665647. The next prime is 201665671. The reversal of 201665664 is 466566102.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32889 + ... + 38535.

It is an arithmetic number, because the mean of its divisors is an integer number (6241040).

Almost surely, 2^201665664 is an apocalyptic number.

201665664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 201665664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (299569920).

201665664 is an abundant number, since it is smaller than the sum of its proper divisors (397474176).

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

201665664 is a wasteful number, since it uses less digits than its factorization.

201665664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5698 (or 5683 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 201665664 is about 14200.9036332200. The cubic root of 201665664 is about 586.4225384623.

The spelling of 201665664 in words is "two hundred one million, six hundred sixty-five thousand, six hundred sixty-four".