1644016399 has 4 divisors (see below), whose sum is σ = 1740723264. Its totient is φ = 1547309536.

The previous prime is 1644016391. The next prime is 1644016469. The reversal of 1644016399 is 9936104461.

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

It is not a de Polignac number, because 1644016399 - 2³ = 1644016391 is a prime.

It is a super-3 number, since 3×1644016399³ (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 (1644016391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48353407 + ... + 48353440.

It is an arithmetic number, because the mean of its divisors is an integer number (435180816).

Almost surely, 2^1644016399 is an apocalyptic number.

1644016399 is a deficient number, since it is larger than the sum of its proper divisors (96706865).

1644016399 is an equidigital number, since it uses as much as digits as its factorization.

1644016399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96706864.

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 1644016399 is about 40546.4720906764. The cubic root of 1644016399 is about 1180.2356129630.

The spelling of 1644016399 in words is "one billion, six hundred forty-four million, sixteen thousand, three hundred ninety-nine".