1664690688 has 240 divisors, whose sum is σ = 5094048960. Its totient is φ = 522289152.

The previous prime is 1664690641. The next prime is 1664690689. The reversal of 1664690688 is 8860964661.

It is not an unprimeable number, because it can be changed into a prime (1664690689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11976123 + ... + 11976261.

It is an arithmetic number, because the mean of its divisors is an integer number (21225204).

Almost surely, 2^1664690688 is an apocalyptic number.

1664690688 is a gapful number since it is divisible by the number (18) 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 1664690688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2547024480).

1664690688 is an abundant number, since it is smaller than the sum of its proper divisors (3429358272).

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

1664690688 is a wasteful number, since it uses less digits than its factorization.

1664690688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The square root of 1664690688 is about 40800.6211717420. The cubic root of 1664690688 is about 1185.1623598505.

The spelling of 1664690688 in words is "one billion, six hundred sixty-four million, six hundred ninety thousand, six hundred eighty-eight".