1644312605 has 8 divisors (see below), whose sum is σ = 2124957912. Its totient is φ = 1214261568.

The previous prime is 1644312601. The next prime is 1644312613. The reversal of 1644312605 is 5062134461.

It can be written as a sum of positive squares in 4 ways, for example, as 234610489 + 1409702116 = 15317^2 + 37546^2 .

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

It is not a de Polignac number, because 1644312605 - 2² = 1644312601 is a prime.

It is a super-3 number, since 3×1644312605³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644312601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12648494 + ... + 12648623.

It is an arithmetic number, because the mean of its divisors is an integer number (265619739).

Almost surely, 2^1644312605 is an apocalyptic number.

It is an amenable number.

1644312605 is a deficient number, since it is larger than the sum of its proper divisors (480645307).

1644312605 is a wasteful number, since it uses less digits than its factorization.

1644312605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25297135.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 1644312605 is about 40550.1245990687. The cubic root of 1644312605 is about 1180.3064905765.

The spelling of 1644312605 in words is "one billion, six hundred forty-four million, three hundred twelve thousand, six hundred five".