206640 has 120 divisors (see below), whose sum is σ = 812448. Its totient is φ = 46080.
The previous prime is 206639. The next prime is 206641. The reversal of 206640 is 46602.
206640 = 502 + 512 + ... + 902.
206640 is a `hidden beast` number, since 2 + 0 + 664 + 0 = 666.
It is an interprime number because it is at equal distance from previous prime (206639) and next prime (206641).
It is a tau number, because it is divible by the number of its divisors (120).
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a nialpdrome in base 14.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 206640.
It is not an unprimeable number, because it can be changed into a prime (206641) by changing a digit.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5020 + ... + 5060.
2206640 is an apocalyptic number.
206640 is a gapful number since it is divisible by the number (20) 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 206640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (406224).
206640 is an abundant number, since it is smaller than the sum of its proper divisors (605808).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
206640 is a wasteful number, since it uses less digits than its factorization.
206640 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 67 (or 58 counting only the distinct ones).
The product of its (nonzero) digits is 288, while the sum is 18.
The square root of 206640 is about 454.5767261970. The cubic root of 206640 is about 59.1205044504.
The spelling of 206640 in words is "two hundred six thousand, six hundred forty".
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