1664531280 has 60 divisors (see below), whose sum is σ = 5590053300. Its totient is φ = 443874816.

The previous prime is 1664531279. The next prime is 1664531293. The reversal of 1664531280 is 821354661.

It is a happy number.

1664531280 is a `hidden beast` number, since 1 + 6 + 645 + 3 + 1 + 2 + 8 + 0 = 666.

1664531280 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 459330624 + 1205200656 = 21432^2 + 34716^2 .

It is a tau number, because it is divible by the number of its divisors (60).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1155205 + ... + 1156644.

It is an arithmetic number, because the mean of its divisors is an integer number (93167555).

Almost surely, 2^1664531280 is an apocalyptic number.

1664531280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664531280 is an abundant number, since it is smaller than the sum of its proper divisors (3925522020).

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

1664531280 is a wasteful number, since it uses less digits than its factorization.

1664531280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2311868 (or 2311859 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 1664531280 is about 40798.6676253036. The cubic root of 1664531280 is about 1185.1245289202.

The spelling of 1664531280 in words is "one billion, six hundred sixty-four million, five hundred thirty-one thousand, two hundred eighty".