1664821704 has 192 divisors, whose sum is σ = 5194506240. Its totient is φ = 435352320.

The previous prime is 1664821681. The next prime is 1664821709. The reversal of 1664821704 is 4071284661.

It is a super-2 number, since 2×1664821704² = 5543262612218927232, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664821709) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5422719 + ... + 5423025.

It is an arithmetic number, because the mean of its divisors is an integer number (27054720).

Almost surely, 2^1664821704 is an apocalyptic number.

1664821704 is a gapful number since it is divisible by the number (14) 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 1664821704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2597253120).

1664821704 is an abundant number, since it is smaller than the sum of its proper divisors (3529684536).

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

1664821704 is a wasteful number, since it uses less digits than its factorization.

1664821704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540 (or 523 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 1664821704 is about 40802.2267039435. The cubic root of 1664821704 is about 1185.1934509434.

The spelling of 1664821704 in words is "one billion, six hundred sixty-four million, eight hundred twenty-one thousand, seven hundred four".