1644468481 has 4 divisors (see below), whose sum is σ = 1650320964. Its totient is φ = 1638616000.

The previous prime is 1644468457. The next prime is 1644468533. The reversal of 1644468481 is 1848644461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 663526081 + 980942400 = 25759^2 + 31320^2 .

It is a cyclic number.

It is not a de Polignac number, because 1644468481 - 2⁹ = 1644467969 is a prime.

It is a super-2 number, since 2×1644468481² = 5408553170004894722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1644469481) 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, 2925820 + ... + 2926381.

It is an arithmetic number, because the mean of its divisors is an integer number (412580241).

Almost surely, 2^1644468481 is an apocalyptic number.

It is an amenable number.

1644468481 is a deficient number, since it is larger than the sum of its proper divisors (5852483).

1644468481 is an equidigital number, since it uses as much as digits as its factorization.

1644468481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5852482.

The product of its digits is 589824, while the sum is 46.

The square root of 1644468481 is about 40552.0465698095. The cubic root of 1644468481 is about 1180.3437859263.

The spelling of 1644468481 in words is "one billion, six hundred forty-four million, four hundred sixty-eight thousand, four hundred eighty-one".