1664425720 has 32 divisors (see below), whose sum is σ = 3792369600. Its totient is φ = 657341568.

The previous prime is 1664425717. The next prime is 1664425733. The reversal of 1664425720 is 275244661.

It is a self number, because there is not a number n which added to its sum of digits gives 1664425720.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260199 + ... + 266518.

It is an arithmetic number, because the mean of its divisors is an integer number (118511550).

Almost surely, 2^1664425720 is an apocalyptic number.

1664425720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664425720 is an abundant number, since it is smaller than the sum of its proper divisors (2127943880).

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

1664425720 is a wasteful number, since it uses less digits than its factorization.

1664425720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526807 (or 526803 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 37.

The square root of 1664425720 is about 40797.3739350954. The cubic root of 1664425720 is about 1185.0994759436.

The spelling of 1664425720 in words is "one billion, six hundred sixty-four million, four hundred twenty-five thousand, seven hundred twenty".