1664403918 has 8 divisors (see below), whose sum is σ = 3328807848. Its totient is φ = 554801304.

The previous prime is 1664403913. The next prime is 1664403929. The reversal of 1664403918 is 8193044661.

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

1664403918 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 1664403918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664403911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138700321 + ... + 138700332.

It is an arithmetic number, because the mean of its divisors is an integer number (416100981).

Almost surely, 2^1664403918 is an apocalyptic number.

1664403918 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1664403918 is a wasteful number, since it uses less digits than its factorization.

1664403918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277400658.

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 1664403918 is about 40797.1067356498. The cubic root of 1664403918 is about 1185.0943014558.

The spelling of 1664403918 in words is "one billion, six hundred sixty-four million, four hundred three thousand, nine hundred eighteen".