1644009689 has 8 divisors (see below), whose sum is σ = 1910713920. Its totient is φ = 1385266896.

The previous prime is 1644009683. The next prime is 1644009707. The reversal of 1644009689 is 9869004461.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1644009689 - 2⁴ = 1644009673 is a prime.

It is a super-3 number, since 3×1644009689³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1644009683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1989914 + ... + 1990739.

It is an arithmetic number, because the mean of its divisors is an integer number (238839240).

Almost surely, 2^1644009689 is an apocalyptic number.

It is an amenable number.

1644009689 is a deficient number, since it is larger than the sum of its proper divisors (266704231).

1644009689 is an equidigital number, since it uses as much as digits as its factorization.

1644009689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3980719.

The product of its (nonzero) digits is 373248, while the sum is 47.

The square root of 1644009689 is about 40546.3893460318. The cubic root of 1644009689 is about 1180.2340072630.

The spelling of 1644009689 in words is "one billion, six hundred forty-four million, nine thousand, six hundred eighty-nine".