1664189856 has 72 divisors (see below), whose sum is σ = 5408623584. Its totient is φ = 475482240.

The previous prime is 1664189851. The next prime is 1664189867. The reversal of 1664189856 is 6589814661.

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (1664189851) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 410730 + ... + 414761.

It is an arithmetic number, because the mean of its divisors is an integer number (75119772).

Almost surely, 2^1664189856 is an apocalyptic number.

1664189856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1664189856 is an abundant number, since it is smaller than the sum of its proper divisors (3744433728).

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

1664189856 is a wasteful number, since it uses less digits than its factorization.

1664189856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825514 (or 825503 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The square root of 1664189856 is about 40794.4831564269. The cubic root of 1664189856 is about 1185.0434935700.

The spelling of 1664189856 in words is "one billion, six hundred sixty-four million, one hundred eighty-nine thousand, eight hundred fifty-six".