1664664660 has 72 divisors (see below), whose sum is σ = 5212386816. Its totient is φ = 429589440.

The previous prime is 1664664643. The next prime is 1664664671. The reversal of 1664664660 is 664664661.

It is a super-2 number, since 2×1664664660² = 5542216860505831200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 143584 + ... + 154743.

Almost surely, 2^1664664660 is an apocalyptic number.

1664664660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664664660 is an abundant number, since it is smaller than the sum of its proper divisors (3547722156).

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

1664664660 is a wasteful number, since it uses less digits than its factorization.

1664664660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298373 (or 298368 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The square root of 1664664660 is about 40800.3022047631. The cubic root of 1664664660 is about 1185.1561830140.

Subtracting from 1664664660 its reverse (664664661), we obtain a palindrome (999999999).

The spelling of 1664664660 in words is "one billion, six hundred sixty-four million, six hundred sixty-four thousand, six hundred sixty".