1644004004 has 12 divisors (see below), whose sum is σ = 2902468044. Its totient is φ = 814727424.

The previous prime is 1644004003. The next prime is 1644004027. The reversal of 1644004004 is 4004004461.

It can be written as a sum of positive squares in 2 ways, for example, as 779526400 + 864477604 = 27920^2 + 29402^2 .

1644004004 is a modest number, since divided by 4004 gives 1644 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1644004001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1818137 + ... + 1819040.

It is an arithmetic number, because the mean of its divisors is an integer number (241872337).

Almost surely, 2^1644004004 is an apocalyptic number.

It is an amenable number.

1644004004 is a deficient number, since it is larger than the sum of its proper divisors (1258464040).

1644004004 is a wasteful number, since it uses less digits than its factorization.

1644004004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3637294 (or 3637292 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 1644004004 is about 40546.3192410853. The cubic root of 1644004004 is about 1180.2326468415.

Adding to 1644004004 its reverse (4004004461), we get a palindrome (5648008465).

It can be divided in two parts, 164 and 4004004, that multiplied together give a palindrome (656656656).

The spelling of 1644004004 in words is "one billion, six hundred forty-four million, four thousand, four".