643974144 has 352 divisors, whose sum is σ = 2122329600. Its totient is φ = 171048960.

The previous prime is 643974137. The next prime is 643974151. The reversal of 643974144 is 441479346.

It is an interprime number because it is at equal distance from previous prime (643974137) and next prime (643974151).

It is a tau number, because it is divible by the number of its divisors (352).

It is a junction number, because it is equal to n+sod(n) for n = 643974096 and 643974105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10914787 + ... + 10914845.

Almost surely, 2^643974144 is an apocalyptic number.

643974144 is a gapful number since it is divisible by the number (64) 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 643974144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1061164800).

643974144 is an abundant number, since it is smaller than the sum of its proper divisors (1478355456).

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

643974144 is a wasteful number, since it uses less digits than its factorization.

643974144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 111 counting only the distinct ones).

The product of its digits is 290304, while the sum is 42.

The square root of 643974144 is about 25376.6456412190. The cubic root of 643974144 is about 863.5539535783.

The spelling of 643974144 in words is "six hundred forty-three million, nine hundred seventy-four thousand, one hundred forty-four".