1664185605 has 8 divisors (see below), whose sum is σ = 2662696992. Its totient is φ = 887565648.

The previous prime is 1664185583. The next prime is 1664185643. The reversal of 1664185605 is 5065814661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1664185605 - 2⁸ = 1664185349 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55472839 + ... + 55472868.

It is an arithmetic number, because the mean of its divisors is an integer number (332837124).

Almost surely, 2^1664185605 is an apocalyptic number.

1664185605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664185605 is a deficient number, since it is larger than the sum of its proper divisors (998511387).

1664185605 is a wasteful number, since it uses less digits than its factorization.

1664185605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110945715.

The product of its (nonzero) digits is 172800, while the sum is 42.

The square root of 1664185605 is about 40794.4310537603. The cubic root of 1664185605 is about 1185.0424845457.

The spelling of 1664185605 in words is "one billion, six hundred sixty-four million, one hundred eighty-five thousand, six hundred five".