1643705140 has 96 divisors (see below), whose sum is σ = 4339577088. Its totient is φ = 512265600.

The previous prime is 1643705113. The next prime is 1643705149. The reversal of 1643705140 is 415073461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643705149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 181930 + ... + 190750.

It is an arithmetic number, because the mean of its divisors is an integer number (45203928).

Almost surely, 2^1643705140 is an apocalyptic number.

1643705140 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 1643705140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2169788544).

1643705140 is an abundant number, since it is smaller than the sum of its proper divisors (2695871948).

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

1643705140 is a wasteful number, since it uses less digits than its factorization.

1643705140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8870 (or 8846 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 1643705140 is about 40542.6336095720. The cubic root of 1643705140 is about 1180.1611242205.

The spelling of 1643705140 in words is "one billion, six hundred forty-three million, seven hundred five thousand, one hundred forty".