1660664720 has 160 divisors (see below), whose sum is σ = 4803442560. Its totient is φ = 524574720.

The previous prime is 1660664711. The next prime is 1660664723. The reversal of 1660664720 is 274660661.

It is not an unprimeable number, because it can be changed into a prime (1660664723) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 190211 + ... + 198749.

It is an arithmetic number, because the mean of its divisors is an integer number (30021516).

Almost surely, 2^1660664720 is an apocalyptic number.

1660664720 is a gapful number since it is divisible by the number (10) 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 1660664720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2401721280).

1660664720 is an abundant number, since it is smaller than the sum of its proper divisors (3142777840).

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

1660664720 is a wasteful number, since it uses less digits than its factorization.

1660664720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8593 (or 8587 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 1660664720 is about 40751.2542138276. The cubic root of 1660664720 is about 1184.2061707262.

The spelling of 1660664720 in words is "one billion, six hundred sixty million, six hundred sixty-four thousand, seven hundred twenty".