1664629380 has 60 divisors (see below), whose sum is σ = 5222009100. Its totient is φ = 443900736.

The previous prime is 1664629333. The next prime is 1664629381. The reversal of 1664629380 is 839264661.

1664629380 is a `hidden beast` number, since 16 + 6 + 4 + 629 + 3 + 8 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 273637764 + 1390991616 = 16542^2 + 37296^2 .

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 (45).

It is not an unprimeable number, because it can be changed into a prime (1664629381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 512155 + ... + 515394.

It is an arithmetic number, because the mean of its divisors is an integer number (87033485).

Almost surely, 2^1664629380 is an apocalyptic number.

1664629380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664629380 is an abundant number, since it is smaller than the sum of its proper divisors (3557379720).

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

1664629380 is a wasteful number, since it uses less digits than its factorization.

1664629380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027570 (or 1027559 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 1664629380 is about 40799.8698527336. The cubic root of 1664629380 is about 1185.1478104357.

The spelling of 1664629380 in words is "one billion, six hundred sixty-four million, six hundred twenty-nine thousand, three hundred eighty".