1644312505 has 16 divisors (see below), whose sum is σ = 2279176704. Its totient is φ = 1125518080.

The previous prime is 1644312491. The next prime is 1644312511. The reversal of 1644312505 is 5052134461.

It is a happy number.

It is not a de Polignac number, because 1644312505 - 2⁵ = 1644312473 is a prime.

It is a super-3 number, since 3×1644312505³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 878377 + ... + 880246.

It is an arithmetic number, because the mean of its divisors is an integer number (142448544).

Almost surely, 2^1644312505 is an apocalyptic number.

It is an amenable number.

1644312505 is a deficient number, since it is larger than the sum of its proper divisors (634864199).

1644312505 is a wasteful number, since it uses less digits than its factorization.

1644312505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1758656.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 1644312505 is about 40550.1233660269. The cubic root of 1644312505 is about 1180.3064666494.

Adding to 1644312505 its reverse (5052134461), we get a palindrome (6696446966).

The spelling of 1644312505 in words is "one billion, six hundred forty-four million, three hundred twelve thousand, five hundred five".