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643998 = 23181593
BaseRepresentation
bin10011101001110011110
31012201101210
42131032132
5131101443
621445250
75321355
oct2351636
91181353
10643998
113aa933
12270826
13197184
1412a99c
15cac33
hex9d39e

643998 has 16 divisors (see below), whose sum is σ = 1297296. Its totient is φ = 213120.

The previous prime is 643991. The next prime is 644009. The reversal of 643998 is 899346.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643991) by changing a digit.

643998 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 790 + ... + 1382.

It is an arithmetic number, because the mean of its divisors is an integer number (81081).

2643998 is an apocalyptic number.

643998 is an abundant number, since it is smaller than the sum of its proper divisors (653298).

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

643998 is a wasteful number, since it uses less digits than its factorization.

643998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779.

The product of its digits is 46656, while the sum is 39.

The square root of 643998 is about 802.4948597966. The cubic root of 643998 is about 86.3564616889.

The spelling of 643998 in words is "six hundred forty-three thousand, nine hundred ninety-eight".

Divisors: 1 2 3 6 181 362 543 593 1086 1186 1779 3558 107333 214666 321999 643998