1644115440 has 160 divisors (see below), whose sum is σ = 5802057216. Its totient is φ = 381230080.

The previous prime is 1644115439. The next prime is 1644115453. The reversal of 1644115440 is 445114461.

It is a super-3 number, since 3×1644115440³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1644115398 and 1644115407.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 47182 + ... + 74258.

Almost surely, 2^1644115440 is an apocalyptic number.

1644115440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1644115440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2901028608).

1644115440 is an abundant number, since it is smaller than the sum of its proper divisors (4157941776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1644115440 is a wasteful number, since it uses less digits than its factorization.

1644115440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27127 (or 27121 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 1644115440 is about 40547.6933992552. The cubic root of 1644115440 is about 1180.2593129229.

The spelling of 1644115440 in words is "one billion, six hundred forty-four million, one hundred fifteen thousand, four hundred forty".