1664544420 has 144 divisors (see below), whose sum is σ = 6295056768. Its totient is φ = 345876480.

The previous prime is 1664544389. The next prime is 1664544421. The reversal of 1664544420 is 244454661.

1664544420 is a `hidden beast` number, since 1 + 6 + 645 + 4 + 4 + 4 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1664544421) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 46189 + ... + 73908.

It is an arithmetic number, because the mean of its divisors is an integer number (43715672).

Almost surely, 2^1664544420 is an apocalyptic number.

1664544420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664544420 is an abundant number, since it is smaller than the sum of its proper divisors (4630512348).

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

1664544420 is a wasteful number, since it uses less digits than its factorization.

1664544420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120130 (or 120125 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

The square root of 1664544420 is about 40798.8286596564. The cubic root of 1664544420 is about 1185.1276474148.

The spelling of 1664544420 in words is "one billion, six hundred sixty-four million, five hundred forty-four thousand, four hundred twenty".