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23640 has 32 divisors (see below), whose sum is σ = 71280. Its totient is φ = 6272.

The previous prime is 23633. The next prime is 23663. The reversal of 23640 is 4632.

It can be divided in two parts, 236 and 40, that added together give a triangular number (276 = T23).

23640 is nontrivially palindromic in base 14.

It is a Harshad number since it is a multiple of its sum of digits (15).

23640 is a nontrivial repdigit in base 14.

It is a plaindrome in base 14.

It is a nialpdrome in base 14.

It is a zygodrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22 + ... + 218.

223640 is an apocalyptic number.

23640 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 23640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35640).

23640 is an abundant number, since it is smaller than the sum of its proper divisors (47640).

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

23640 is a wasteful number, since it uses less digits than its factorization.

23640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 23640 is about 153.7530487503. The cubic root of 23640 is about 28.7000392542.

The spelling of 23640 in words is "twenty-three thousand, six hundred forty".