1664444660 has 12 divisors (see below), whose sum is σ = 3495333828. Its totient is φ = 665777856.

The previous prime is 1664444659. The next prime is 1664444689. The reversal of 1664444660 is 664444661.

It can be written as a sum of positive squares in 2 ways, for example, as 585059344 + 1079385316 = 24188^2 + 32854^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41611097 + ... + 41611136.

It is an arithmetic number, because the mean of its divisors is an integer number (291277819).

Almost surely, 2^1664444660 is an apocalyptic number.

1664444660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664444660 is an abundant number, since it is smaller than the sum of its proper divisors (1830889168).

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

1664444660 is a wasteful number, since it uses less digits than its factorization.

1664444660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83222242 (or 83222240 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 41.

The square root of 1664444660 is about 40797.6060572186. The cubic root of 1664444660 is about 1185.1039711275.

Subtracting from 1664444660 its reverse (664444661), we obtain a palindrome (999999999).

The spelling of 1664444660 in words is "one billion, six hundred sixty-four million, four hundred forty-four thousand, six hundred sixty".