1644311340 has 240 divisors, whose sum is σ = 5969601792. Its totient is φ = 371101824.

The previous prime is 1644311323. The next prime is 1644311353. The reversal of 1644311340 is 431134461.

1644311340 is a `hidden beast` number, since 1 + 6 + 4 + 4 + 311 + 340 = 666.

It is a super-3 number, since 3×1644311340³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 79 ways as a sum of consecutive naturals, for example, 940347 + ... + 942093.

Almost surely, 2^1644311340 is an apocalyptic number.

1644311340 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 1644311340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2984800896).

1644311340 is an abundant number, since it is smaller than the sum of its proper divisors (4325290452).

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

1644311340 is a wasteful number, since it uses less digits than its factorization.

1644311340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1858 (or 1847 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 1644311340 is about 40550.1090010865. The cubic root of 1644311340 is about 1180.3061878992.

The spelling of 1644311340 in words is "one billion, six hundred forty-four million, three hundred eleven thousand, three hundred forty".