1644663273 has 32 divisors (see below), whose sum is σ = 2440891392. Its totient is φ = 976622400.

The previous prime is 1644663253. The next prime is 1644663287. The reversal of 1644663273 is 3723664461.

It is not a de Polignac number, because 1644663273 - 2¹³ = 1644655081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1644663233) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 568236 + ... + 571122.

It is an arithmetic number, because the mean of its divisors is an integer number (76277856).

Almost surely, 2^1644663273 is an apocalyptic number.

It is an amenable number.

1644663273 is a deficient number, since it is larger than the sum of its proper divisors (796228119).

1644663273 is a wasteful number, since it uses less digits than its factorization.

1644663273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3245.

The product of its digits is 435456, while the sum is 42.

The square root of 1644663273 is about 40554.4482517023. The cubic root of 1644663273 is about 1180.3903891199.

The spelling of 1644663273 in words is "one billion, six hundred forty-four million, six hundred sixty-three thousand, two hundred seventy-three".