1664167680 has 360 divisors, whose sum is σ = 6808335072. Its totient is φ = 380215296.

The previous prime is 1664167663. The next prime is 1664167709. The reversal of 1664167680 is 867614661.

1664167680 is a `hidden beast` number, since 166 + 416 + 76 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 724614 + ... + 726906.

Almost surely, 2^1664167680 is an apocalyptic number.

1664167680 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 1664167680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3404167536).

1664167680 is an abundant number, since it is smaller than the sum of its proper divisors (5144167392).

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

1664167680 is an equidigital number, since it uses as much as digits as its factorization.

1664167680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2333 (or 2310 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 1664167680 is about 40794.2113540635. The cubic root of 1664167680 is about 1185.0382298194.

The spelling of 1664167680 in words is "one billion, six hundred sixty-four million, one hundred sixty-seven thousand, six hundred eighty".